The electron is a subatomic particle, symbol e− or β−, whose
electric charge is negative one elementary charge. Electrons belong
to the first generation of the lepton particle family, and are
generally thought to be elementary particles because they have no
known components or substructure. The electron has a mass that is
approximately 1/1836 that of the proton. Quantum mechanical
properties of the electron include an intrinsic angular momentum
(spin) of a half-integer value, expressed in units of the reduced
Planck constant, ħ. As it is a fermion, no two electrons can occupy
the same quantum state, in accordance with the Pauli exclusion
principle. Like all elementary particles, electrons exhibit
properties of both particles and waves: they can collide with other
particles and can be diffracted like light. The wave properties of
electrons are easier to observe with experiments than those of other
particles like neutrons and protons because electrons have a lower
mass and hence a longer de Broglie wavelength for a given energy.
Electrons play an essential role in numerous physical phenomena, such
as electricity, magnetism, chemistry and thermal conductivity, and
they also participate in gravitational, electromagnetic and weak
interactions. Since an electron has charge, it has a surrounding
electric field, and if that electron is moving relative to an observer
it will generate a magnetic field. Electromagnetic fields produced
from other sources will affect the motion of an electron according to
Lorentz force law. Electrons radiate or absorb energy in the form
of photons when they are accelerated. Laboratory instruments are
capable of trapping individual electrons as well as electron plasma by
the use of electromagnetic fields.
Special telescopes can detect
electron plasma in outer space. Electrons are involved in many
applications such as electronics, welding, cathode ray tubes, electron
microscopes, radiation therapy, lasers, gaseous ionization detectors
and particle accelerators.
Interactions involving electrons with other subatomic particles are of
interest in fields such as chemistry and nuclear physics. The Coulomb
force interaction between the positive protons within atomic nuclei
and the negative electrons without, allows the composition of the two
known as atoms. Ionization or differences in the proportions of
negative electrons versus positive nuclei changes the binding energy
of an atomic system. The exchange or sharing of the electrons between
two or more atoms is the main cause of chemical bonding. In 1838,
British natural philosopher
Richard Laming first hypothesized the
concept of an indivisible quantity of electric charge to explain the
chemical properties of atoms. Irish physicist George Johnstone
Stoney named this charge 'electron' in 1891, and
J. J. Thomson
J. J. Thomson and his
team of British physicists identified it as a particle in
1897. Electrons can also participate in nuclear reactions,
such as nucleosynthesis in stars, where they are known as beta
particles. Electrons can be created through beta decay of radioactive
isotopes and in high-energy collisions, for instance when cosmic rays
enter the atmosphere. The antiparticle of the electron is called the
positron; it is identical to the electron except that it carries
electrical and other charges of the opposite sign. When an electron
collides with a positron, both particles can be totally annihilated,
producing gamma ray photons.
1.2 Atomic theory
1.3 Quantum mechanics
1.5 Confinement of individual electrons
2.2 Fundamental properties
2.3 Quantum properties
2.4 Virtual particles
2.6 Atoms and molecules
2.8 Motion and energy
5 Plasma applications
5.3 Other applications
6 See also
9 External links
See also: History of electromagnetism
The ancient Greeks noticed that amber attracted small objects when
rubbed with fur. Along with lightning, this phenomenon is one of
humanity's earliest recorded experiences with electricity. In his
1600 treatise De Magnete, the English scientist William Gilbert coined
New Latin term electricus, to refer to this property of attracting
small objects after being rubbed. Both electric and electricity
are derived from the Latin ēlectrum (also the root of the alloy of
the same name), which came from the Greek word for amber,
In the early 1700s,
Francis Hauksbee and French chemist Charles
François du Fay independently discovered what they believed were two
kinds of frictional electricity—one generated from rubbing glass,
the other from rubbing resin. From this, du Fay theorized that
electricity consists of two electrical fluids, vitreous and resinous,
that are separated by friction, and that neutralize each other when
combined. American scientist
Ebenezer Kinnersley later also
independently reached the same conclusion.:118 A decade later
Benjamin Franklin proposed that electricity was not from different
types of electrical fluid, but a single electrical fluid showing an
excess (+) or deficit (-). He gave them the modern charge nomenclature
of positive and negative respectively. Franklin thought of the
charge carrier as being positive, but he did not correctly identify
which situation was a surplus of the charge carrier, and which
situation was a deficit.
Between 1838 and 1851, British natural philosopher Richard Laming
developed the idea that an atom is composed of a core of matter
surrounded by subatomic particles that had unit electric charges.
Beginning in 1846, German physicist William Weber theorized that
electricity was composed of positively and negatively charged fluids,
and their interaction was governed by the inverse square law. After
studying the phenomenon of electrolysis in 1874, Irish physicist
George Johnstone Stoney
George Johnstone Stoney suggested that there existed a "single
definite quantity of electricity", the charge of a monovalent ion. He
was able to estimate the value of this elementary charge e by means of
Faraday's laws of electrolysis. However, Stoney believed these
charges were permanently attached to atoms and could not be removed.
In 1881, German physicist
Hermann von Helmholtz
Hermann von Helmholtz argued that both
positive and negative charges were divided into elementary parts, each
of which "behaves like atoms of electricity".
Stoney initially coined the term electrolion in 1881. Ten years later,
he switched to electron to describe these elementary charges, writing
in 1894: "... an estimate was made of the actual amount of this most
remarkable fundamental unit of electricity, for which I have since
ventured to suggest the name electron". A 1906 proposal to change to
electrion failed because
Hendrik Lorentz preferred to keep
electron. The word electron is a combination of the words
electric and ion. The suffix -on which is now used to designate
other subatomic particles, such as a proton or neutron, is in turn
derived from electron.
A beam of electrons deflected in a circle by a magnetic field
Electron detected in an isopropanol cloud chamber
The German physicist
Johann Wilhelm Hittorf
Johann Wilhelm Hittorf studied electrical
conductivity in rarefied gases: in 1869, he discovered a glow emitted
from the cathode that increased in size with decrease in gas pressure.
In 1876, the German physicist
Eugen Goldstein showed that the rays
from this glow cast a shadow, and he dubbed the rays cathode rays.
During the 1870s, the English chemist and physicist Sir William
Crookes developed the first cathode ray tube to have a high vacuum
inside. He then showed that the luminescence rays appearing within
the tube carried energy and moved from the cathode to the anode.
Furthermore, by applying a magnetic field, he was able to deflect the
rays, thereby demonstrating that the beam behaved as though it were
negatively charged. In 1879, he proposed that these properties
could be explained by what he termed 'radiant matter'. He suggested
that this was a fourth state of matter, consisting of negatively
charged molecules that were being projected with high velocity from
The German-born British physicist
Arthur Schuster expanded upon
Crookes' experiments by placing metal plates parallel to the cathode
rays and applying an electric potential between the plates. The field
deflected the rays toward the positively charged plate, providing
further evidence that the rays carried negative charge. By measuring
the amount of deflection for a given level of current, in 1890
Schuster was able to estimate the charge-to-mass ratio of the ray
components. However, this produced a value that was more than a
thousand times greater than what was expected, so little credence was
given to his calculations at the time.
Hendrik Lorentz suggested that the mass of these particles
(electrons) could be a consequence of their electric charge.
In 1896, the British physicist J. J. Thomson, with his colleagues John
S. Townsend and H. A. Wilson, performed experiments indicating
that cathode rays really were unique particles, rather than waves,
atoms or molecules as was believed earlier. Thomson made good
estimates of both the charge e and the mass m, finding that cathode
ray particles, which he called "corpuscles," had perhaps one
thousandth of the mass of the least massive ion known:
hydrogen. He showed that their charge-to-mass ratio, e/m, was
independent of cathode material. He further showed that the negatively
charged particles produced by radioactive materials, by heated
materials and by illuminated materials were universal. The name
electron was again proposed for these particles by the Irish physicist
George Johnstone Stoney, and the name has since gained universal
While studying naturally fluorescing minerals in 1896, the French
Henri Becquerel discovered that they emitted radiation
without any exposure to an external energy source. These radioactive
materials became the subject of much interest by scientists, including
the New Zealand physicist
Ernest Rutherford who discovered they
emitted particles. He designated these particles alpha and beta, on
the basis of their ability to penetrate matter. In 1900, Becquerel
showed that the beta rays emitted by radium could be deflected by an
electric field, and that their mass-to-charge ratio was the same as
for cathode rays. This evidence strengthened the view that
electrons existed as components of atoms.
The electron's charge was more carefully measured by the American
physicists Robert Millikan and
Harvey Fletcher in their oil-drop
experiment of 1909, the results of which were published in 1911. This
experiment used an electric field to prevent a charged droplet of oil
from falling as a result of gravity. This device could measure the
electric charge from as few as 1–150 ions with an error margin of
less than 0.3%. Comparable experiments had been done earlier by
Thomson's team, using clouds of charged water droplets generated by
electrolysis, and in 1911 by Abram Ioffe, who independently
obtained the same result as Millikan using charged microparticles of
metals, then published his results in 1913. However, oil drops
were more stable than water drops because of their slower evaporation
rate, and thus more suited to precise experimentation over longer
periods of time.
Around the beginning of the twentieth century, it was found that under
certain conditions a fast-moving charged particle caused a
condensation of supersaturated water vapor along its path. In 1911,
Charles Wilson used this principle to devise his cloud chamber so he
could photograph the tracks of charged particles, such as fast-moving
See also: The proton–electron model of the nucleus
Bohr model of the atom, showing states of electron with energy
quantized by the number n. An electron dropping to a lower orbit emits
a photon equal to the energy difference between the orbits.
By 1914, experiments by physicists Ernest Rutherford, Henry Moseley,
James Franck and Gustav Hertz had largely established the structure of
an atom as a dense nucleus of positive charge surrounded by lower-mass
electrons. In 1913, Danish physicist
Niels Bohr postulated that
electrons resided in quantized energy states, with their energies
determined by the angular momentum of the electron's orbit about the
nucleus. The electrons could move between those states, or orbits, by
the emission or absorption of photons of specific frequencies. By
means of these quantized orbits, he accurately explained the spectral
lines of the hydrogen atom. However, Bohr's model failed to
account for the relative intensities of the spectral lines and it was
unsuccessful in explaining the spectra of more complex atoms.
Chemical bonds between atoms were explained by Gilbert Newton Lewis,
who in 1916 proposed that a covalent bond between two atoms is
maintained by a pair of electrons shared between them. Later, in
Walter Heitler and
Fritz London gave the full explanation of the
electron-pair formation and chemical bonding in terms of quantum
mechanics. In 1919, the American chemist Irving Langmuir
elaborated on the Lewis' static model of the atom and suggested that
all electrons were distributed in successive "concentric (nearly)
spherical shells, all of equal thickness". In turn, he divided the
shells into a number of cells each of which contained one pair of
electrons. With this model Langmuir was able to qualitatively explain
the chemical properties of all elements in the periodic table,
which were known to largely repeat themselves according to the
In 1924, Austrian physicist
Wolfgang Pauli observed that the
shell-like structure of the atom could be explained by a set of four
parameters that defined every quantum energy state, as long as each
state was occupied by no more than a single electron. This prohibition
against more than one electron occupying the same quantum energy state
became known as the Pauli exclusion principle. The physical
mechanism to explain the fourth parameter, which had two distinct
possible values, was provided by the Dutch physicists Samuel Goudsmit
and George Uhlenbeck. In 1925, they suggested that an electron, in
addition to the angular momentum of its orbit, possesses an intrinsic
angular momentum and magnetic dipole moment. This is analogous
to the rotation of the Earth on its axis as it orbits the Sun. The
intrinsic angular momentum became known as spin, and explained the
previously mysterious splitting of spectral lines observed with a
high-resolution spectrograph; this phenomenon is known as fine
See also: History of quantum mechanics
In his 1924 dissertation Recherches sur la théorie des quanta
(Research on Quantum Theory), French physicist Louis de Broglie
hypothesized that all matter can be represented as a de Broglie wave
in the manner of light. That is, under the appropriate conditions,
electrons and other matter would show properties of either particles
or waves. The corpuscular properties of a particle are demonstrated
when it is shown to have a localized position in space along its
trajectory at any given moment. The wave-like nature of light is
displayed, for example, when a beam of light is passed through
parallel slits thereby creating interference patterns. In 1927 George
Paget Thomson, discovered the interference effect was produced when a
beam of electrons was passed through thin metal foils and by American
Clinton Davisson and
Lester Germer by the reflection of
electrons from a crystal of nickel.
In quantum mechanics, the behavior of an electron in an atom is
described by an orbital, which is a probability distribution rather
than an orbit. In the figure, the shading indicates the relative
probability to "find" the electron, having the energy corresponding to
the given quantum numbers, at that point.
De Broglie's prediction of a wave nature for electrons led Erwin
Schrödinger to postulate a wave equation for electrons moving under
the influence of the nucleus in the atom. In 1926, this equation, the
Schrödinger equation, successfully described how electron waves
propagated. Rather than yielding a solution that determined the
location of an electron over time, this wave equation also could be
used to predict the probability of finding an electron near a
position, especially a position near where the electron was bound in
space, for which the electron wave equations did not change in time.
This approach led to a second formulation of quantum mechanics (the
first by Heisenberg in 1925), and solutions of Schrödinger's
equation, like Heisenberg's, provided derivations of the energy states
of an electron in a hydrogen atom that were equivalent to those that
had been derived first by Bohr in 1913, and that were known to
reproduce the hydrogen spectrum. Once spin and the interaction
between multiple electrons were describable, quantum mechanics made it
possible to predict the configuration of electrons in atoms with
atomic numbers greater than hydrogen.
In 1928, building on Wolfgang Pauli's work,
Paul Dirac produced a
model of the electron – the Dirac equation, consistent with
relativity theory, by applying relativistic and symmetry
considerations to the hamiltonian formulation of the quantum mechanics
of the electro-magnetic field. In order to resolve some problems
within his relativistic equation, Dirac developed in 1930 a model of
the vacuum as an infinite sea of particles with negative energy, later
dubbed the Dirac sea. This led him to predict the existence of a
positron, the antimatter counterpart of the electron. This
particle was discovered in 1932 by Carl Anderson, who proposed calling
standard electrons negatrons, and using electron as a generic term to
describe both the positively and negatively charged variants.
In 1947 Willis Lamb, working in collaboration with graduate student
Robert Retherford, found that certain quantum states of the hydrogen
atom, which should have the same energy, were shifted in relation to
each other, the difference came to be called the Lamb shift. About the
same time, Polykarp Kusch, working with Henry M. Foley, discovered the
magnetic moment of the electron is slightly larger than predicted by
Dirac's theory. This small difference was later called anomalous
magnetic dipole moment of the electron. This difference was later
explained by the theory of quantum electrodynamics, developed by
Julian Schwinger and
Richard Feynman in the late
With the development of the particle accelerator during the first half
of the twentieth century, physicists began to delve deeper into the
properties of subatomic particles. The first successful attempt to
accelerate electrons using electromagnetic induction was made in 1942
by Donald Kerst. His initial betatron reached energies of
2.3 MeV, while subsequent betatrons achieved 300 MeV. In
1947, synchrotron radiation was discovered with a 70 MeV electron
synchrotron at General Electric. This radiation was caused by the
acceleration of electrons through a magnetic field as they moved near
the speed of light.
With a beam energy of 1.5 GeV, the first high-energy particle
collider was ADONE, which began operations in 1968. This device
accelerated electrons and positrons in opposite directions,
effectively doubling the energy of their collision when compared to
striking a static target with an electron. The Large
Collider (LEP) at CERN, which was operational from
1989 to 2000, achieved collision energies of 209 GeV and made
important measurements for the
Standard Model of particle
Confinement of individual electrons
Individual electrons can now be easily confined in ultra small (L = 20
nm, W = 20 nm) CMOS transistors operated at cryogenic temperature over
a range of −269 °C (4 K) to about −258 °C
(15 K). The electron wavefunction spreads in a semiconductor
lattice and negligibly interacts with the valence band electrons, so
it can be treated in the single particle formalism, by replacing its
mass with the effective mass tensor.
Standard Model of elementary particles. The electron (symbol e) is on
Standard Model of particle physics, electrons belong to the
group of subatomic particles called leptons, which are believed to be
fundamental or elementary particles. Electrons have the lowest mass of
any charged lepton (or electrically charged particle of any type) and
belong to the first-generation of fundamental particles. The
second and third generation contain charged leptons, the muon and the
tau, which are identical to the electron in charge, spin and
interactions, but are more massive. Leptons differ from the other
basic constituent of matter, the quarks, by their lack of strong
interaction. All members of the lepton group are fermions, because
they all have half-odd integer spin; the electron has spin 1/2.
The invariant mass of an electron is approximately
6969910900000000000♠9.109×10−31 kilograms, or
6996548900000000000♠5.489×10−4 atomic mass units. On the
basis of Einstein's principle of mass–energy equivalence, this mass
corresponds to a rest energy of 0.511 MeV. The ratio between the
mass of a proton and that of an electron is about 1836.
Astronomical measurements show that the proton-to-electron mass ratio
has held the same value, as is predicted by the Standard Model, for at
least half the age of the universe.
Electrons have an electric charge of
3018839800000000000♠−1.602×10−19 coulomb, which is used as
a standard unit of charge for subatomic particles, and is also called
the elementary charge. This elementary charge has a relative standard
uncertainty of 6992220000000000000♠2.2×10−8. Within the
limits of experimental accuracy, the electron charge is identical to
the charge of a proton, but with the opposite sign. As the symbol
e is used for the elementary charge, the electron is commonly
symbolized by e−, where the minus sign indicates the negative
charge. The positron is symbolized by e+ because it has the same
properties as the electron but with a positive rather than negative
The electron has an intrinsic angular momentum or spin of 1/2.
This property is usually stated by referring to the electron as a
spin-1/2 particle. For such particles the spin magnitude is
√3/2 ħ.[note 3] while the result of the measurement of a
projection of the spin on any axis can only be ±ħ/2. In addition to
spin, the electron has an intrinsic magnetic moment along its spin
axis. It is approximately equal to one Bohr magneton,[note 4]
which is a physical constant equal to
6976927400914999999♠9.27400915(23)×10−24 joules per
tesla. The orientation of the spin with respect to the momentum of
the electron defines the property of elementary particles known as
The electron has no known substructure and it is assumed to be
a point particle with a point charge and no spatial extent. In
classical physics, the angular momentum and magnetic moment of an
object depend upon its physical dimensions. Hence, the concept of a
dimensionless electron possessing these properties contrasts to
experimental observations in Penning traps which point to finite
non-zero radius of the electron. A possible
explanation of this paradoxical situation is given below in the
"Virtual particles" subsection by taking into consideration the
The issue of the radius of the electron is a challenging problem of
the modern theoretical physics. The admission of the hypothesis of a
finite radius of the electron is incompatible to the premises of the
theory of relativity. On the other hand, a point-like electron (zero
radius) generates serious mathematical difficulties due to the
self-energy of the electron tending to infinity.
Observation of a single electron in a
Penning trap suggests the upper
limit of the particle's radius to be 10−22 meters. The
upper bound of the electron radius of 10−18 meters can be
derived using the uncertainty relation in energy.
There is also a physical constant called the "classical electron
radius", with the much larger value of
6985281789999999999♠2.8179×10−15 m, greater than the radius
of the proton. However, the terminology comes from a simplistic
calculation that ignores the effects of quantum mechanics; in reality,
the so-called classical electron radius has little to do with the true
fundamental structure of the electron.[note 5]
There are elementary particles that spontaneously decay into less
massive particles. An example is the muon, with a mean lifetime of
6994220000000000000♠2.2×10−6 seconds, which decays into an
electron, a muon neutrino and an electron antineutrino. The electron,
on the other hand, is thought to be stable on theoretical grounds: the
electron is the least massive particle with non-zero electric charge,
so its decay would violate charge conservation. The experimental
lower bound for the electron's mean lifetime is
7028659999999999999♠6.6×1028 years, at a 90% confidence
As with all particles, electrons can act as waves. This is called the
wave–particle duality and can be demonstrated using the double-slit
The wave-like nature of the electron allows it to pass through two
parallel slits simultaneously, rather than just one slit as would be
the case for a classical particle. In quantum mechanics, the wave-like
property of one particle can be described mathematically as a
complex-valued function, the wave function, commonly denoted by the
Greek letter psi (ψ). When the absolute value of this function is
squared, it gives the probability that a particle will be observed
near a location—a probability density.:162–218
Example of an antisymmetric wave function for a quantum state of two
identical fermions in a 1-dimensional box. If the particles swap
position, the wave function inverts its sign.
Electrons are identical particles because they cannot be distinguished
from each other by their intrinsic physical properties. In quantum
mechanics, this means that a pair of interacting electrons must be
able to swap positions without an observable change to the state of
the system. The wave function of fermions, including electrons, is
antisymmetric, meaning that it changes sign when two electrons are
swapped; that is, ψ(r1, r2) = −ψ(r2, r1), where the variables r1
and r2 correspond to the first and second electrons, respectively.
Since the absolute value is not changed by a sign swap, this
corresponds to equal probabilities. Bosons, such as the photon, have
symmetric wave functions instead.:162–218
In the case of antisymmetry, solutions of the wave equation for
interacting electrons result in a zero probability that each pair will
occupy the same location or state. This is responsible for the Pauli
exclusion principle, which precludes any two electrons from occupying
the same quantum state. This principle explains many of the properties
of electrons. For example, it causes groups of bound electrons to
occupy different orbitals in an atom, rather than all overlapping each
other in the same orbit.:162–218
Main article: Virtual particle
In a simplified picture, every photon spends some time as a
combination of a virtual electron plus its antiparticle, the virtual
positron, which rapidly annihilate each other shortly thereafter.
The combination of the energy variation needed to create these
particles, and the time during which they exist, fall under the
threshold of detectability expressed by the Heisenberg uncertainty
relation, ΔE · Δt ≥ ħ. In effect, the energy
needed to create these virtual particles, ΔE, can be "borrowed" from
the vacuum for a period of time, Δt, so that their product is no more
than the reduced Planck constant, ħ ≈
6984660000000000000♠6.6×10−16 eV·s. Thus, for a virtual
electron, Δt is at most
A schematic depiction of virtual electron–positron pairs appearing
at random near an electron (at lower left)
While an electron–positron virtual pair is in existence, the coulomb
force from the ambient electric field surrounding an electron causes a
created positron to be attracted to the original electron, while a
created electron experiences a repulsion. This causes what is called
vacuum polarization. In effect, the vacuum behaves like a medium
having a dielectric permittivity more than unity. Thus the effective
charge of an electron is actually smaller than its true value, and the
charge decreases with increasing distance from the electron.
This polarization was confirmed experimentally in 1997 using the
Japanese TRISTAN particle accelerator. Virtual particles cause a
comparable shielding effect for the mass of the electron.
The interaction with virtual particles also explains the small (about
0.1%) deviation of the intrinsic magnetic moment of the electron from
Bohr magneton (the anomalous magnetic moment). The
extraordinarily precise agreement of this predicted difference with
the experimentally determined value is viewed as one of the great
achievements of quantum electrodynamics.
The apparent paradox (mentioned above in the properties subsection) of
a point particle electron having intrinsic angular momentum and
magnetic moment can be explained by the formation of virtual photons
in the electric field generated by the electron. These photons cause
the electron to shift about in a jittery fashion (known as
zitterbewegung), which results in a net circular motion with
precession. This motion produces both the spin and the magnetic moment
of the electron. In atoms, this creation of virtual photons
Lamb shift observed in spectral lines.
An electron generates an electric field that exerts an attractive
force on a particle with a positive charge, such as the proton, and a
repulsive force on a particle with a negative charge. The strength of
this force in nonrelativistic approximation is determined by Coulomb's
inverse square law.:58–61 When an electron is in motion, it
generates a magnetic field.:140 The Ampère-Maxwell law relates
the magnetic field to the mass motion of electrons (the current) with
respect to an observer. This property of induction supplies the
magnetic field that drives an electric motor. The electromagnetic
field of an arbitrary moving charged particle is expressed by the
Liénard–Wiechert potentials, which are valid even when the
particle's speed is close to that of light
A particle with charge q (at left) is moving with velocity v through a
magnetic field B that is oriented toward the viewer. For an electron,
q is negative so it follows a curved trajectory toward the top.
When an electron is moving through a magnetic field, it is subject to
Lorentz force that acts perpendicularly to the plane defined by
the magnetic field and the electron velocity. This centripetal force
causes the electron to follow a helical trajectory through the field
at a radius called the gyroradius. The acceleration from this curving
motion induces the electron to radiate energy in the form of
synchrotron radiation.:160[note 6] The energy emission in turn
causes a recoil of the electron, known as the
Abraham–Lorentz–Dirac Force, which creates a friction that slows
the electron. This force is caused by a back-reaction of the
electron's own field upon itself.
Photons mediate electromagnetic interactions between particles in
quantum electrodynamics. An isolated electron at a constant velocity
cannot emit or absorb a real photon; doing so would violate
conservation of energy and momentum. Instead, virtual photons can
transfer momentum between two charged particles. This exchange of
virtual photons, for example, generates the
Coulomb force. Energy
emission can occur when a moving electron is deflected by a charged
particle, such as a proton. The acceleration of the electron results
in the emission of
Bremsstrahlung is produced by an electron e deflected by the
electric field of an atomic nucleus. The energy change
E2 − E1 determines the frequency f of the emitted photon.
An inelastic collision between a photon (light) and a solitary (free)
electron is called Compton scattering. This collision results in a
transfer of momentum and energy between the particles, which modifies
the wavelength of the photon by an amount called the Compton
shift.[note 7] The maximum magnitude of this wavelength shift is
h/mec, which is known as the Compton wavelength. For an electron,
it has a value of 6988243000000000000♠2.43×10−12 m. When
the wavelength of the light is long (for instance, the wavelength of
the visible light is 0.4–0.7 μm) the wavelength shift becomes
negligible. Such interaction between the light and free electrons is
Thomson scattering or Linear Thomson scattering.
The relative strength of the electromagnetic interaction between two
charged particles, such as an electron and a proton, is given by the
fine-structure constant. This value is a dimensionless quantity formed
by the ratio of two energies: the electrostatic energy of attraction
(or repulsion) at a separation of one Compton wavelength, and the rest
energy of the charge. It is given by
α ≈ 6997729735300000000♠7.297353×10−3, which is
approximately equal to 1/137.
When electrons and positrons collide, they annihilate each other,
giving rise to two or more gamma ray photons. If the electron and
positron have negligible momentum, a positronium atom can form before
annihilation results in two or three gamma ray photons totalling
1.022 MeV. On the other hand, high-energy photons can
transform into an electron and a positron by a process called pair
production, but only in the presence of a nearby charged particle,
such as a nucleus.
In the theory of electroweak interaction, the left-handed component of
electron's wavefunction forms a weak isospin doublet with the electron
neutrino. This means that during weak interactions, electron neutrinos
behave like electrons. Either member of this doublet can undergo a
charged current interaction by emitting or absorbing a W and be
converted into the other member. Charge is conserved during this
reaction because the
W boson also carries a charge, canceling out any
net change during the transmutation.
Charged current interactions are
responsible for the phenomenon of beta decay in a radioactive atom.
Both the electron and electron neutrino can undergo a neutral current
interaction via a Z0 exchange, and this is responsible for
neutrino-electron elastic scattering.
Atoms and molecules
Main article: Atom
Probability densities for the first few hydrogen atom orbitals, seen
in cross-section. The energy level of a bound electron determines the
orbital it occupies, and the color reflects the probability of finding
the electron at a given position.
An electron can be bound to the nucleus of an atom by the attractive
Coulomb force. A system of one or more electrons bound to a nucleus is
called an atom. If the number of electrons is different from the
nucleus' electrical charge, such an atom is called an ion. The
wave-like behavior of a bound electron is described by a function
called an atomic orbital. Each orbital has its own set of quantum
numbers such as energy, angular momentum and projection of angular
momentum, and only a discrete set of these orbitals exist around the
nucleus. According to the
Pauli exclusion principle
Pauli exclusion principle each orbital can
be occupied by up to two electrons, which must differ in their spin
Electrons can transfer between different orbitals by the emission or
absorption of photons with an energy that matches the difference in
potential. Other methods of orbital transfer include collisions
with particles, such as electrons, and the Auger effect. To
escape the atom, the energy of the electron must be increased above
its binding energy to the atom. This occurs, for example, with the
photoelectric effect, where an incident photon exceeding the atom's
ionization energy is absorbed by the electron.
The orbital angular momentum of electrons is quantized. Because the
electron is charged, it produces an orbital magnetic moment that is
proportional to the angular momentum. The net magnetic moment of an
atom is equal to the vector sum of orbital and spin magnetic moments
of all electrons and the nucleus. The magnetic moment of the nucleus
is negligible compared with that of the electrons. The magnetic
moments of the electrons that occupy the same orbital (so called,
paired electrons) cancel each other out.
The chemical bond between atoms occurs as a result of electromagnetic
interactions, as described by the laws of quantum mechanics. The
strongest bonds are formed by the sharing or transfer of electrons
between atoms, allowing the formation of molecules. Within a
molecule, electrons move under the influence of several nuclei, and
occupy molecular orbitals; much as they can occupy atomic orbitals in
isolated atoms. A fundamental factor in these molecular
structures is the existence of electron pairs. These are electrons
with opposed spins, allowing them to occupy the same molecular orbital
without violating the
Pauli exclusion principle
Pauli exclusion principle (much like in atoms).
Different molecular orbitals have different spatial distribution of
the electron density. For instance, in bonded pairs (i.e. in the pairs
that actually bind atoms together) electrons can be found with the
maximal probability in a relatively small volume between the nuclei.
By contrast, in non-bonded pairs electrons are distributed in a large
volume around nuclei.
A lightning discharge consists primarily of a flow of electrons.
The electric potential needed for lightning can be generated by a
If a body has more or fewer electrons than are required to balance the
positive charge of the nuclei, then that object has a net electric
charge. When there is an excess of electrons, the object is said to be
negatively charged. When there are fewer electrons than the number of
protons in nuclei, the object is said to be positively charged. When
the number of electrons and the number of protons are equal, their
charges cancel each other and the object is said to be electrically
neutral. A macroscopic body can develop an electric charge through
rubbing, by the triboelectric effect.
Independent electrons moving in vacuum are termed free electrons.
Electrons in metals also behave as if they were free. In reality the
particles that are commonly termed electrons in metals and other
solids are quasi-electrons—quasiparticles, which have the same
electrical charge, spin, and magnetic moment as real electrons but
might have a different mass. When free electrons—both in vacuum
and metals—move, they produce a net flow of charge called an
electric current, which generates a magnetic field. Likewise a current
can be created by a changing magnetic field. These interactions are
described mathematically by Maxwell's equations.
At a given temperature, each material has an electrical conductivity
that determines the value of electric current when an electric
potential is applied. Examples of good conductors include metals such
as copper and gold, whereas glass and Teflon are poor conductors. In
any dielectric material, the electrons remain bound to their
respective atoms and the material behaves as an insulator. Most
semiconductors have a variable level of conductivity that lies between
the extremes of conduction and insulation. On the other hand,
metals have an electronic band structure containing partially filled
electronic bands. The presence of such bands allows electrons in
metals to behave as if they were free or delocalized electrons. These
electrons are not associated with specific atoms, so when an electric
field is applied, they are free to move like a gas (called Fermi
gas) through the material much like free electrons.
Because of collisions between electrons and atoms, the drift velocity
of electrons in a conductor is on the order of millimeters per second.
However, the speed at which a change of current at one point in the
material causes changes in currents in other parts of the material,
the velocity of propagation, is typically about 75% of light
speed. This occurs because electrical signals propagate as a
wave, with the velocity dependent on the dielectric constant of the
Metals make relatively good conductors of heat, primarily because the
delocalized electrons are free to transport thermal energy between
atoms. However, unlike electrical conductivity, the thermal
conductivity of a metal is nearly independent of temperature. This is
expressed mathematically by the Wiedemann–Franz law, which
states that the ratio of thermal conductivity to the electrical
conductivity is proportional to the temperature. The thermal disorder
in the metallic lattice increases the electrical resistivity of the
material, producing a temperature dependence for electric
When cooled below a point called the critical temperature, materials
can undergo a phase transition in which they lose all resistivity to
electric current, in a process known as superconductivity. In BCS
theory, this behavior is modeled by pairs of electrons entering a
quantum state known as a Bose–Einstein condensate. These Cooper
pairs have their motion coupled to nearby matter via lattice
vibrations called phonons, thereby avoiding the collisions with atoms
that normally create electrical resistance. (Cooper pairs have a
radius of roughly 100 nm, so they can overlap each other.)
However, the mechanism by which higher temperature superconductors
operate remains uncertain.
Electrons inside conducting solids, which are quasi-particles
themselves, when tightly confined at temperatures close to absolute
zero, behave as though they had split into three other quasiparticles:
spinons, orbitons and holons. The former carries spin and
magnetic moment, the next carries its orbital location while the
latter electrical charge.
Motion and energy
According to Einstein's theory of special relativity, as an electron's
speed approaches the speed of light, from an observer's point of view
its relativistic mass increases, thereby making it more and more
difficult to accelerate it from within the observer's frame of
reference. The speed of an electron can approach, but never reach, the
speed of light in a vacuum, c. However, when relativistic
electrons—that is, electrons moving at a speed close to c—are
injected into a dielectric medium such as water, where the local speed
of light is significantly less than c, the electrons temporarily
travel faster than light in the medium. As they interact with the
medium, they generate a faint light called Cherenkov radiation.
Lorentz factor as a function of velocity. It starts at value 1 and
goes to infinity as v approaches c.
The effects of special relativity are based on a quantity known as the
Lorentz factor, defined as
displaystyle scriptstyle gamma =1/ sqrt 1- v^ 2 / c^ 2
where v is the speed of the particle. The kinetic energy Ke of an
electron moving with velocity v is:
displaystyle displaystyle K_ mathrm e =(gamma -1)m_ mathrm e
c^ 2 ,
where me is the mass of electron. For example, the Stanford linear
accelerator can accelerate an electron to roughly 51 GeV.
Since an electron behaves as a wave, at a given velocity it has a
characteristic de Broglie wavelength. This is given by
λe = h/p where h is the
Planck constant and p is the
momentum. For the 51 GeV electron above, the wavelength is
about 6983240000000000000♠2.4×10−17 m, small enough to
explore structures well below the size of an atomic nucleus.
Pair production caused by the collision of a photon with an atomic
Big Bang theory is the most widely accepted scientific theory to
explain the early stages in the evolution of the Universe. For
the first millisecond of the Big Bang, the temperatures were over
10 billion kelvins and photons had mean energies over a
million electronvolts. These photons were sufficiently energetic that
they could react with each other to form pairs of electrons and
positrons. Likewise, positron-electron pairs annihilated each other
and emitted energetic photons:
γ + γ ↔ e+ + e−
An equilibrium between electrons, positrons and photons was maintained
during this phase of the evolution of the Universe. After 15 seconds
had passed, however, the temperature of the universe dropped below the
threshold where electron-positron formation could occur. Most of the
surviving electrons and positrons annihilated each other, releasing
gamma radiation that briefly reheated the universe.
For reasons that remain uncertain, during the annihilation process
there was an excess in the number of particles over antiparticles.
Hence, about one electron for every billion electron-positron pairs
survived. This excess matched the excess of protons over antiprotons,
in a condition known as baryon asymmetry, resulting in a net charge of
zero for the universe. The surviving protons and neutrons
began to participate in reactions with each other—in the process
known as nucleosynthesis, forming isotopes of hydrogen and helium,
with trace amounts of lithium. This process peaked after about five
minutes. Any leftover neutrons underwent negative beta decay with
a half-life of about a thousand seconds, releasing a proton and
electron in the process,
n → p + e− + ν
For about the next
the excess electrons remained too energetic to bind with atomic
nuclei. What followed is a period known as recombination, when
neutral atoms were formed and the expanding universe became
transparent to radiation.
Roughly one million years after the big bang, the first generation of
stars began to form. Within a star, stellar nucleosynthesis
results in the production of positrons from the fusion of atomic
nuclei. These antimatter particles immediately annihilate with
electrons, releasing gamma rays. The net result is a steady reduction
in the number of electrons, and a matching increase in the number of
neutrons. However, the process of stellar evolution can result in the
synthesis of radioactive isotopes. Selected isotopes can subsequently
undergo negative beta decay, emitting an electron and antineutrino
from the nucleus. An example is the cobalt-60 (60Co) isotope,
which decays to form nickel-60 (60Ni).
An extended air shower generated by an energetic cosmic ray striking
the Earth's atmosphere
At the end of its lifetime, a star with more than about 20 solar
masses can undergo gravitational collapse to form a black hole.
According to classical physics, these massive stellar objects exert a
gravitational attraction that is strong enough to prevent anything,
even electromagnetic radiation, from escaping past the Schwarzschild
radius. However, quantum mechanical effects are believed to
potentially allow the emission of
Hawking radiation at this distance.
Electrons (and positrons) are thought to be created at the event
horizon of these stellar remnants.
When a pair of virtual particles (such as an electron and positron) is
created in the vicinity of the event horizon, random spatial
positioning might result in one of them to appear on the exterior;
this process is called quantum tunnelling. The gravitational potential
of the black hole can then supply the energy that transforms this
virtual particle into a real particle, allowing it to radiate away
into space. In exchange, the other member of the pair is given
negative energy, which results in a net loss of mass-energy by the
black hole. The rate of
Hawking radiation increases with decreasing
mass, eventually causing the black hole to evaporate away until,
finally, it explodes.
Cosmic rays are particles traveling through space with high energies.
Energy events as high as 7001480652946100000♠3.0×1020 eV have
been recorded. When these particles collide with nucleons in the
Earth's atmosphere, a shower of particles is generated, including
pions. More than half of the cosmic radiation observed from the
Earth's surface consists of muons. The particle called a muon is a
lepton produced in the upper atmosphere by the decay of a pion.
π− → μ− + ν
A muon, in turn, can decay to form an electron or positron.
μ− → e− + ν
e + ν
Aurorae are mostly caused by energetic electrons precipitating into
Remote observation of electrons requires detection of their radiated
energy. For example, in high-energy environments such as the corona of
a star, free electrons form a plasma that radiates energy due to
Electron gas can undergo plasma oscillation,
which is waves caused by synchronized variations in electron density,
and these produce energy emissions that can be detected by using radio
The frequency of a photon is proportional to its energy. As a bound
electron transitions between different energy levels of an atom, it
absorbs or emits photons at characteristic frequencies. For instance,
when atoms are irradiated by a source with a broad spectrum, distinct
absorption lines appear in the spectrum of transmitted radiation. Each
element or molecule displays a characteristic set of spectral lines,
such as the hydrogen spectral series. Spectroscopic measurements of
the strength and width of these lines allow the composition and
physical properties of a substance to be determined.
In laboratory conditions, the interactions of individual electrons can
be observed by means of particle detectors, which allow measurement of
specific properties such as energy, spin and charge. The
development of the Paul trap and
Penning trap allows charged particles
to be contained within a small region for long durations. This enables
precise measurements of the particle properties. For example, in one
Penning trap was used to contain a single electron for a
period of 10 months. The magnetic moment of the electron was
measured to a precision of eleven digits, which, in 1980, was a
greater accuracy than for any other physical constant.
The first video images of an electron's energy distribution were
captured by a team at
Lund University in Sweden, February 2008. The
scientists used extremely short flashes of light, called attosecond
pulses, which allowed an electron's motion to be observed for the
The distribution of the electrons in solid materials can be visualized
by angle-resolved photoemission spectroscopy (ARPES). This technique
employs the photoelectric effect to measure the reciprocal space—a
mathematical representation of periodic structures that is used to
infer the original structure. ARPES can be used to determine the
direction, speed and scattering of electrons within the material.
NASA wind tunnel test, a model of the
Space Shuttle is
targeted by a beam of electrons, simulating the effect of ionizing
gases during re-entry.
Electron beams are used in welding. They allow energy densities
up to 7007100000000000000♠107 W·cm−2 across a narrow focus
diameter of 0.1–1.3 mm and usually require no filler material. This
welding technique must be performed in a vacuum to prevent the
electrons from interacting with the gas before reaching their target,
and it can be used to join conductive materials that would otherwise
be considered unsuitable for welding.
Electron-beam lithography (EBL) is a method of etching semiconductors
at resolutions smaller than a micrometer. This technique is
limited by high costs, slow performance, the need to operate the beam
in the vacuum and the tendency of the electrons to scatter in solids.
The last problem limits the resolution to about 10 nm. For this
reason, EBL is primarily used for the production of small numbers of
specialized integrated circuits.
Electron beam processing
Electron beam processing is used to irradiate materials in order to
change their physical properties or sterilize medical and food
Electron beams fluidise or quasi-melt glasses without
significant increase of temperature on intensive irradiation: e.g.
intensive electron radiation causes a many orders of magnitude
decrease of viscosity and stepwise decrease of its activation
Linear particle accelerators generate electron beams for treatment of
superficial tumors in radiation therapy.
Electron therapy can treat
such skin lesions as basal-cell carcinomas because an electron beam
only penetrates to a limited depth before being absorbed, typically up
to 5 cm for electron energies in the range 5–20 MeV. An
electron beam can be used to supplement the treatment of areas that
have been irradiated by X-rays.
Particle accelerators use electric fields to propel electrons and
their antiparticles to high energies. These particles emit synchrotron
radiation as they pass through magnetic fields. The dependency of the
intensity of this radiation upon spin polarizes the electron beam—a
process known as the Sokolov–Ternov effect.[note 8] Polarized
electron beams can be useful for various experiments. Synchrotron
radiation can also cool the electron beams to reduce the momentum
spread of the particles.
Electron and positron beams are collided upon
the particles' accelerating to the required energies; particle
detectors observe the resulting energy emissions, which particle
physics studies .
Low-energy electron diffraction
Low-energy electron diffraction (LEED) is a method of bombarding a
crystalline material with a collimated beam of electrons and then
observing the resulting diffraction patterns to determine the
structure of the material. The required energy of the electrons is
typically in the range 20–200 eV. The reflection
high-energy electron diffraction (RHEED) technique uses the reflection
of a beam of electrons fired at various low angles to characterize the
surface of crystalline materials. The beam energy is typically in the
range 8–20 keV and the angle of incidence is 1–4°.
The electron microscope directs a focused beam of electrons at a
specimen. Some electrons change their properties, such as movement
direction, angle, and relative phase and energy as the beam interacts
with the material. Microscopists can record these changes in the
electron beam to produce atomically resolved images of the
material. In blue light, conventional optical microscopes have a
diffraction-limited resolution of about 200 nm. By
comparison, electron microscopes are limited by the de Broglie
wavelength of the electron. This wavelength, for example, is equal to
0.0037 nm for electrons accelerated across a 100,000-volt
potential. The Transmission
Microscope is capable of sub-0.05 nm resolution, which is more
than enough to resolve individual atoms. This capability makes
the electron microscope a useful laboratory instrument for high
resolution imaging. However, electron microscopes are expensive
instruments that are costly to maintain.
Two main types of electron microscopes exist: transmission and
scanning. Transmission electron microscopes function like overhead
projectors, with a beam of electrons passing through a slice of
material then being projected by lenses on a photographic slide or a
charge-coupled device. Scanning electron microscopes rasteri a finely
focused electron beam, as in a TV set, across the studied sample to
produce the image. Magnifications range from 100× to 1,000,000× or
higher for both microscope types. The scanning tunneling microscope
uses quantum tunneling of electrons from a sharp metal tip into the
studied material and can produce atomically resolved images of its
In the free-electron laser (FEL), a relativistic electron beam passes
through a pair of undulators that contain arrays of dipole magnets
whose fields point in alternating directions. The electrons emit
synchrotron radiation that coherently interacts with the same
electrons to strongly amplify the radiation field at the resonance
frequency. FEL can emit a coherent high-brilliance electromagnetic
radiation with a wide range of frequencies, from microwaves to soft
X-rays. These devices are used in manufacturing, communication, and in
medical applications, such as soft tissue surgery.
Electrons are important in cathode ray tubes, which have been
extensively used as display devices in laboratory instruments,
computer monitors and television sets. In a photomultiplier tube,
every photon striking the photocathode initiates an avalanche of
electrons that produces a detectable current pulse.
use the flow of electrons to manipulate electrical signals, and they
played a critical role in the development of electronics technology.
However, they have been largely supplanted by solid-state devices such
as the transistor.
Periodic systems of small molecules
List of particles
^ The fractional version's denominator is the inverse of the decimal
value (along with its relative standard uncertainty of
^ The electron's charge is the negative of elementary charge, which
has a positive value for the proton.
^ This magnitude is obtained from the spin quantum number as
displaystyle begin alignedat 2 S&= sqrt s(s+1) cdot frac
h 2pi \&= frac sqrt 3 2 hbar \end alignedat
for quantum number s = 1/2.
See: Gupta, M.C. (2001). Atomic and Molecular Spectroscopy. New Age
Publishers. p. 81. ISBN 81-224-1300-5.
^ Bohr magneton:
displaystyle textstyle mu _ mathrm B = frac ehbar 2m_
mathrm e .
^ The classical electron radius is derived as follows. Assume that the
electron's charge is spread uniformly throughout a spherical volume.
Since one part of the sphere would repel the other parts, the sphere
contains electrostatic potential energy. This energy is assumed to
equal the electron's rest energy, defined by special relativity
(E = mc2).
From electrostatics theory, the potential energy of a sphere with
radius r and charge e is given by:
displaystyle E_ mathrm p = frac e^ 2 8pi varepsilon _ 0 r
where ε0 is the vacuum permittivity. For an electron with rest mass
m0, the rest energy is equal to:
displaystyle textstyle E_ mathrm p =m_ 0 c^ 2 ,
where c is the speed of light in a vacuum. Setting them equal and
solving for r gives the classical electron radius.
See: Haken, H.; Wolf, H.C.; Brewer, W.D. (2005). The
Physics of Atoms
and Quanta: Introduction to Experiments and Theory. Springer.
p. 70. ISBN 3-540-67274-5.
^ Radiation from non-relativistic electrons is sometimes termed
^ The change in wavelength, Δλ, depends on the angle of the recoil,
θ, as follows,
displaystyle textstyle Delta lambda = frac h m_ mathrm e c
(1-cos theta ),
where c is the speed of light in a vacuum and me is the electron mass.
See Zombeck (2007: 393, 396).
^ The polarization of an electron beam means that the spins of all
electrons point into one direction. In other words, the projections of
the spins of all electrons onto their momentum vector have the same
^ a b c Eichten, E.J.; Peskin, M.E.; Peskin, M. (1983). "New Tests for
Physical Review Letters. 50 (11):
^ a b Farrar, W.V. (1969). "
Richard Laming and the Coal-Gas Industry,
with His Views on the Structure of Matter". Annals of Science. 25 (3):
^ a b c Arabatzis, T. (2006). Representing Electrons: A Biographical
Approach to Theoretical Entities. University of Chicago Press.
pp. 70–74. ISBN 0-226-02421-0.
^ Buchwald, J.Z.; Warwick, A. (2001). Histories of the Electron: The
Birth of Microphysics. MIT Press. pp. 195–203.
^ a b c d e f Thomson, J.J. (1897). "
Cathode Rays". Philosophical
Magazine. 44 (269): 293–316. doi:10.1080/14786449708621070.
^ a b c d e P.J. Mohr, B.N. Taylor, and D.B. Newell, "The 2014 CODATA
Recommended Values of the Fundamental Physical Constants". This
database was developed by J. Baker, M. Douma, and S. Kotochigova.
Available: . National Institute of Standards and Technology,
Gaithersburg, MD 20899.
^ a b Agostini M. et al. (
Borexino Coll.) (2015). "Test of Electric
Charge Conservation with Borexino".
Physical Review Letters. 115 (23):
231802. arXiv:1509.01223 . Bibcode:2015PhRvL.115w1802A.
doi:10.1103/PhysRevLett.115.231802. PMID 26684111.
^ "JERRY COFF". Retrieved 10 September 2010.
^ a b c d Curtis, L.J. (2003). Atomic Structure and Lifetimes: A
Conceptual Approach. Cambridge University Press. p. 74.
^ a b "CODATA value: proton-electron mass ratio". 2006 CODATA
recommended values. National Institute of Standards and Technology.
^ Anastopoulos, C. (2008).
Particle Or Wave: The Evolution of the
Concept of Matter in Modern Physics. Princeton University Press.
pp. 236–237. ISBN 0-691-13512-6.
^ a b Pauling, L.C. (1960). The Nature of the Chemical Bond and the
Structure of Molecules and Crystals: an introduction to modern
structural chemistry (3rd ed.). Cornell University Press.
pp. 4–10. ISBN 0-8014-0333-2.
^ a b c Dahl (1997:122–185).
^ a b Wilson, R. (1997). Astronomy Through the Ages: The Story of the
Human Attempt to Understand the Universe. CRC Press. p. 138.
^ Shipley, J.T. (1945). Dictionary of Word Origins. The Philosophical
Library. p. 133. ISBN 0-88029-751-4.
^ Baigrie, B. (2006).
Electricity and Magnetism: A Historical
Perspective. Greenwood Press. pp. 7–8.
^ Keithley, J.F. (1999). The Story of Electrical and Magnetic
Measurements: From 500 B.C. to the 1940s.
IEEE Press. pp. 15, 20.
^ Florian Cajori (1917). A History of
Physics in Its Elementary
Branches: Including the Evolution of Physical Laboratories.
Benjamin Franklin (1706–1790)". Eric Weisstein's World of
Biography. Wolfram Research. Retrieved 2010-12-16.
^ Myers, R.L. (2006). The Basics of Physics. Greenwood Publishing
Group. p. 242. ISBN 0-313-32857-9.
^ Barrow, J.D. (1983). "Natural Units Before Planck". Quarterly
Journal of the Royal Astronomical Society. 24: 24–26.
^ Sōgo Okamura (1994). History of
Electron Tubes. IOS Press.
p. 11. ISBN 978-90-5199-145-1. Retrieved 29 May 2015. In
1881, Stoney named this electromagnetic 'electrolion'. It came to be
called 'electron' from 1891. [...] In 1906, the suggestion to call
cathode ray particles 'electrions' was brought up but through the
opinion of Lorentz of Holland 'electrons' came to be widely
^ Stoney, G.J. (1894). "Of the "Electron," or
Atom of Electricity".
Philosophical Magazine. 38 (5): 418–420.
^ "electron, n.2". OED Online. March 2013. Oxford University Press.
Accessed 12 April 2013 
^ Soukhanov, A.H. ed. (1986). Word Mysteries & Histories. Houghton
Mifflin Company. p. 73. ISBN 0-395-40265-4. CS1 maint:
Extra text: authors list (link)
^ Guralnik, D.B. ed. (1970). Webster's New World Dictionary. Prentice
Hall. p. 450. CS1 maint: Extra text: authors list (link)
^ Born, M.; Blin-Stoyle, R.J.; Radcliffe, J.M. (1989). Atomic Physics.
Courier Dover. p. 26. ISBN 0-486-65984-4.
^ Dahl (1997:55–58).
^ DeKosky, R.K. (1983). "
William Crookes and the quest for absolute
vacuum in the 1870s". Annals of Science. 40 (1): 1–18.
^ a b Leicester, H.M. (1971). The Historical Background of Chemistry.
Courier Dover. pp. 221–222. ISBN 0-486-61053-5.
^ Dahl (1997:64–78).
^ Zeeman, P.; Zeeman, P. (1907). "Sir William Crookes, F.R.S". Nature.
77 (1984): 1–3. Bibcode:1907Natur..77....1C.
^ Dahl (1997:99).
^ Frank Wilczek: "Happy Birthday, Electron" Scientific American, June
^ Thomson, J.J. (1906). "Nobel Lecture: Carriers of Negative
Electricity" (PDF). The Nobel Foundation. Retrieved 2008-08-25.
^ Trenn, T.J. (1976). "Rutherford on the Alpha-Beta-Gamma
Classification of Radioactive Rays". Isis. 67 (1): 61–75.
doi:10.1086/351545. JSTOR 231134.
^ Becquerel, H. (1900). "Déviation du Rayonnement du
Radium dans un
Comptes rendus de l'Académie des sciences (in
French). 130: 809–815.
^ Buchwald and Warwick (2001:90–91).
^ Myers, W.G. (1976). "Becquerel's Discovery of Radioactivity in
1896". Journal of Nuclear Medicine. 17 (7): 579–582.
^ Kikoin, I.K.; Sominskiĭ, I.S. (1961). "Abram Fedorovich Ioffe (on
his eightieth birthday)". Soviet
Physics Uspekhi. 3 (5): 798–809.
doi:10.1070/PU1961v003n05ABEH005812. Original publication in
Russian: Кикоин, И.К.; Соминский, М.С. (1960).
"Академик А.Ф. Иоффе" (PDF). Успехи
Физических Наук. 72 (10): 303–321.
^ Millikan, R.A. (1911). "The Isolation of an Ion, a Precision
Measurement of its Charge, and the Correction of Stokes' Law".
Physical Review. 32 (2): 349–397. Bibcode:1911PhRvI..32..349M.
^ Das Gupta, N.N.; Ghosh, S.K. (1999). "A Report on the Wilson Cloud
Chamber and Its Applications in Physics". Reviews of Modern Physics.
18 (2): 225–290. Bibcode:1946RvMP...18..225G.
^ a b c Smirnov, B.M. (2003).
Physics of Atoms and Ions. Springer.
pp. 14–21. ISBN 0-387-95550-X.
^ Bohr, N. (1922). "Nobel Lecture: The Structure of the Atom" (PDF).
The Nobel Foundation. Retrieved 2008-12-03.
^ Lewis, G.N. (1916). "The
Atom and the Molecule". Journal of the
American Chemical Society. 38 (4): 762–786.
^ a b Arabatzis, T.; Gavroglu, K. (1997). "The chemists' electron".
European Journal of Physics. 18 (3): 150–163.
^ Langmuir, I. (1919). "The Arrangement of Electrons in Atoms and
Molecules". Journal of the American Chemical Society. 41 (6):
^ Scerri, E.R. (2007). The Periodic Table. Oxford University Press.
pp. 205–226. ISBN 0-19-530573-6.
^ Massimi, M. (2005). Pauli's Exclusion Principle, The Origin and
Validation of a Scientific Principle. Cambridge University Press.
pp. 7–8. ISBN 0-521-83911-4.
^ Uhlenbeck, G.E.; Goudsmith, S. (1925). "Ersetzung der Hypothese vom
unmechanischen Zwang durch eine Forderung bezüglich des inneren
Verhaltens jedes einzelnen Elektrons". Die
German). 13 (47): 953–954. Bibcode:1925NW.....13..953E.
^ Pauli, W. (1923). "Über die Gesetzmäßigkeiten des anomalen
Zeemaneffektes". Zeitschrift für Physik (in German). 16 (1):
155–164. Bibcode:1923ZPhy...16..155P. doi:10.1007/BF01327386.
^ a b de Broglie, L. (1929). "Nobel Lecture: The Wave Nature of the
Electron" (PDF). The Nobel Foundation. Retrieved 2008-08-30.
^ Falkenburg, B. (2007).
Particle Metaphysics: A Critical Account of
Subatomic Reality. Springer. p. 85.
^ Davisson, C. (1937). "Nobel Lecture: The Discovery of Electron
Waves" (PDF). The Nobel Foundation. Retrieved 2008-08-30.
^ Schrödinger, E. (1926). "Quantisierung als Eigenwertproblem".
Annalen der Physik (in German). 385 (13): 437–490.
^ Rigden, J.S. (2003). Hydrogen. Harvard University Press.
pp. 59–86. ISBN 0-674-01252-6.
^ Reed, B.C. (2007). Quantum Mechanics. Jones & Bartlett
Publishers. pp. 275–350. ISBN 0-7637-4451-4.
^ Dirac, P.A.M. (1928). "The Quantum Theory of the Electron".
Proceedings of the Royal Society A. 117 (778): 610–624.
^ Dirac, P.A.M. (1933). "Nobel Lecture: Theory of Electrons and
Positrons" (PDF). The Nobel Foundation. Retrieved 2008-11-01.
^ "The Nobel Prize in
Physics 1965". The Nobel Foundation. Retrieved
^ Panofsky, W.K.H. (1997). "The Evolution of
& Colliders" (PDF). Beam Line. Stanford University. 27 (1):
36–44. Retrieved 2008-09-15.
^ Elder, F.R.; et al. (1947). "Radiation from Electrons in a
Synchrotron". Physical Review. 71 (11): 829–830.
^ Hoddeson, L.; et al. (1997). The Rise of the Standard Model:
Physics in the 1960s and 1970s. Cambridge University Press.
pp. 25–26. ISBN 0-521-57816-7.
^ Bernardini, C. (2004). "AdA: The First Electron–Positron
Physics in Perspective. 6 (2): 156–183.
^ "Testing the Standard Model: The LEP experiments". CERN. 2008.
^ "LEP reaps a final harvest".
CERN Courier. 40 (10). 2000.
^ Prati, E.; De Michielis, M.; Belli, M.; Cocco, S.; Fanciulli, M.;
Kotekar-Patil, D.; Ruoff, M.; Kern, D. P.; Wharam, D. A.; Verduijn,
J.; Tettamanzi, G. C.; Rogge, S.; Roche, B.; Wacquez, R.; Jehl, X.;
Vinet, M.; Sanquer, M. (2012). "Few electron limit of n-type metal
oxide semiconductor single electron transistors". Nanotechnology. 23
(21): 215204. arXiv:1203.4811 . Bibcode:2012Nanot..23u5204P.
doi:10.1088/0957-4484/23/21/215204. PMID 22552118.
^ Frampton, P.H.; Hung, P.Q.; Sher, Marc (2000). "Quarks and Leptons
Beyond the Third Generation".
Physics Reports. 330 (5–6): 263–348.
arXiv:hep-ph/9903387 . Bibcode:2000PhR...330..263F.
^ a b c Raith, W.; Mulvey, T. (2001). Constituents of Matter: Atoms,
Molecules, Nuclei and Particles. CRC Press. pp. 777–781.
^ a b c d e f g h i The original source for CODATA is Mohr, P.J.;
Taylor, B.N.; Newell, D.B. (2006). "CODATA recommended values of the
fundamental physical constants". Reviews of Modern Physics. 80 (2):
633–730. arXiv:0801.0028 . Bibcode:2008RvMP...80..633M.
Individual physical constants from the CODATA are available at: "The
NIST Reference on Constants, Units and Uncertainty". National
Institute of Standards and Technology. Retrieved 2009-01-15.
^ Zombeck, M.V. (2007). Handbook of Space Astronomy and Astrophysics
(3rd ed.). Cambridge University Press. p. 14.
^ Murphy, M.T.; et al. (2008). "Strong Limit on a Variable
Electron Mass Ratio from Molecules in the Distant Universe".
Science. 320 (5883): 1611–1613. arXiv:0806.3081 .
^ Zorn, J.C.; Chamberlain, G.E.; Hughes, V.W. (1963). "Experimental
Limits for the Electron-
Proton Charge Difference and for the Charge of
the Neutron". Physical Review. 129 (6): 2566–2576.
^ a b Odom, B.; et al. (2006). "New Measurement of the Electron
Magnetic Moment Using a One-
Electron Quantum Cyclotron". Physical
Review Letters. 97 (3): 030801. Bibcode:2006PhRvL..97c0801O.
doi:10.1103/PhysRevLett.97.030801. PMID 16907490.
^ Anastopoulos, C. (2008).
Particle Or Wave: The Evolution of the
Concept of Matter in Modern Physics. Princeton University Press.
pp. 261–262. ISBN 0-691-13512-6.
^ Gabrielse, G.; et al. (2006). "New Determination of the Fine
Structure Constant from the
Electron g Value and QED". Physical Review
Letters. 97 (3): 030802(1–4). Bibcode:2006PhRvL..97c0802G.
^ Eduard Shpolsky, Atomic physics (Atomnaia fizika), second edition,
^ Dehmelt, H. (1988). "A Single Atomic
Particle Forever Floating at
Rest in Free Space: New Value for
Electron Radius". Physica Scripta.
T22: 102–10. Bibcode:1988PhST...22..102D.
Gerald Gabrielse webpage at Harvard University
^ Meschede, D. (2004). Optics, light and lasers: The Practical
Approach to Modern Aspects of Photonics and Laser Physics. Wiley-VCH.
p. 168. ISBN 3-527-40364-7.
^ Steinberg, R.I.; et al. (1999). "Experimental test of charge
conservation and the stability of the electron".
Physical Review D. 61
(2): 2582–2586. Bibcode:1975PhRvD..12.2582S.
^ J. Beringer (
Particle Data Group); et al. (2012). "Review of
Particle Physics: [electron properties]" (PDF).
Physical Review D. 86
(1): 010001. Bibcode:2012PhRvD..86a0001B.
^ Back, H. O.; et al. (2002). "Search for electron decay mode e → γ
+ ν with prototype of
Physics Letters B. 525:
^ a b c d e Munowitz, M. (2005). Knowing, The Nature of Physical Law.
Oxford University Press. ISBN 0-19-516737-6.
^ Kane, G. (October 9, 2006). "Are virtual particles really constantly
popping in and out of existence? Or are they merely a mathematical
bookkeeping device for quantum mechanics?". Scientific American.
^ Taylor, J. (1989). "Gauge Theories in
Particle Physics". In Davies,
Paul. The New Physics. Cambridge University Press. p. 464.
^ a b Genz, H. (2001). Nothingness: The Science of Empty Space. Da
Capo Press. pp. 241–243, 245–247.
^ Gribbin, J. (January 25, 1997). "More to electrons than meets the
eye". New Scientist. Retrieved 2008-09-17.
^ Levine, I.; et al. (1997). "Measurement of the Electromagnetic
Coupling at Large
Physical Review Letters. 78 (3):
^ Murayama, H. (March 10–17, 2006). Supersymmetry Breaking Made
Easy, Viable and Generic. Proceedings of the XLIInd Rencontres de
Moriond on Electroweak Interactions and Unified Theories. La Thuile,
Italy. arXiv:0709.3041 . Bibcode:2007arXiv0709.3041M. —lists
a 9% mass difference for an electron that is the size of the Planck
^ Schwinger, J. (1948). "On Quantum-Electrodynamics and the Magnetic
Moment of the Electron". Physical Review. 73 (4): 416–417.
^ Huang, K. (2007). Fundamental Forces of Nature: The Story of Gauge
Fields. World Scientific. pp. 123–125.
^ Foldy, L.L.; Wouthuysen, S. (1950). "On the Dirac Theory of Spin 1/2
Particles and Its Non-Relativistic Limit". Physical Review. 78:
29–36. Bibcode:1950PhRv...78...29F. doi:10.1103/PhysRev.78.29.
^ Sidharth, B.G. (2008). "Revisiting Zitterbewegung". International
Journal of Theoretical Physics. 48 (2): 497–506. arXiv:0806.0985 .
^ a b Griffiths, David J. (1998), Introduction to Electrodynamics (3rd
ed.), Prentice Hall, ISBN 0-13-805326-X
^ Crowell, B. (2000).
Electricity and Magnetism.
Light and Matter.
pp. 129–152. ISBN 0-9704670-4-4.
^ Mahadevan, R.; Narayan, R.; Yi, I. (1996). "Harmony in Electrons:
Synchrotron Emission by Thermal Electrons in a Magnetic
Field". The Astrophysical Journal. 465: 327–337.
arXiv:astro-ph/9601073 . Bibcode:1996ApJ...465..327M.
^ Rohrlich, F. (1999). "The Self-Force and Radiation Reaction".
American Journal of Physics. 68 (12): 1109–1112.
^ Georgi, H. (1989). "Grand Unified Theories". In Davies, Paul. The
New Physics. Cambridge University Press. p. 427.
^ Blumenthal, G.J.; Gould, R. (1970). "Bremsstrahlung, Synchrotron
Radiation, and Compton Scattering of High-Energy Electrons Traversing
Dilute Gases". Reviews of Modern Physics. 42 (2): 237–270.
^ Staff (2008). "The Nobel Prize in
Physics 1927". The Nobel
Foundation. Retrieved 2008-09-28.
^ Chen, S.-Y.; Maksimchuk, A.; Umstadter, D. (1998). "Experimental
observation of relativistic nonlinear Thomson scattering". Nature. 396
(6712): 653–655. arXiv:physics/9810036 .
^ Beringer, R.; Montgomery, C.G. (1942). "The Angular Distribution of
Annihilation Radiation". Physical Review. 61 (5–6):
^ Buffa, A. (2000). College
Physics (4th ed.). Prentice Hall.
p. 888. ISBN 0-13-082444-5.
^ Eichler, J. (2005). "Electron–positron pair production in
relativistic ion–atom collisions".
Physics Letters A. 347 (1–3):
^ Hubbell, J.H. (2006). "
Electron positron pair production by photons:
A historical overview". Radiation
Physics and Chemistry. 75 (6):
^ Quigg, C. (June 4–30, 2000). The Electroweak Theory. TASI 2000:
Physics for the Millennium. Boulder, Colorado. p. 80.
arXiv:hep-ph/0204104 . Bibcode:2002hep.ph....4104Q.
^ Mulliken, R.S. (1967). "Spectroscopy, Molecular Orbitals, and
Chemical Bonding". Science. 157 (3784): 13–24.
^ Burhop, E.H.S. (1952). The Auger Effect and Other Radiationless
Transitions. Cambridge University Press. pp. 2–3.
^ a b Grupen, C. (2000). "
Particle Detection". AIP
Conference Proceedings. 536: 3–34. arXiv:physics/9906063 .
^ Jiles, D. (1998). Introduction to
Magnetism and Magnetic Materials.
CRC Press. pp. 280–287. ISBN 0-412-79860-3.
^ Löwdin, P.O.; Erkki Brändas, E.; Kryachko, E.S. (2003).
Fundamental World of Quantum Chemistry: A Tribute to the Memory of
Per- Olov Löwdin. Springer. pp. 393–394.
^ McQuarrie, D.A.; Simon, J.D. (1997). Physical Chemistry: A Molecular
Approach. University Science Books. pp. 325–361.
^ Daudel, R.; et al. (1974). "The
Electron Pair in Chemistry".
Canadian Journal of Chemistry. 52 (8): 1310–1320.
^ Rakov, V.A.; Uman, M.A. (2007). Lightning:
Physics and Effects.
Cambridge University Press. p. 4. ISBN 0-521-03541-4.
^ Freeman, G.R.; March, N.H. (1999). "Triboelectricity and some
associated phenomena". Materials Science and Technology. 15 (12):
^ Forward, K.M.; Lacks, D.J.; Sankaran, R.M. (2009). "Methodology for
studying particle–particle triboelectrification in granular
materials". Journal of Electrostatics. 67 (2–3): 178–183.
^ Weinberg, S. (2003). The Discovery of Subatomic Particles. Cambridge
University Press. pp. 15–16. ISBN 0-521-82351-X.
^ Lou, L.-F. (2003). Introduction to phonons and electrons. World
Scientific. pp. 162, 164. ISBN 978-981-238-461-4.
^ Guru, B.S.; Hızıroğlu, H.R. (2004). Electromagnetic Field Theory.
Cambridge University Press. pp. 138, 276.
^ Achuthan, M.K.; Bhat, K.N. (2007). Fundamentals of Semiconductor
Devices. Tata McGraw-Hill. pp. 49–67.
^ a b Ziman, J.M. (2001). Electrons and Phonons: The Theory of
Transport Phenomena in Solids. Oxford University Press. p. 260.
^ Main, P. (June 12, 1993). "When electrons go with the flow: Remove
the obstacles that create electrical resistance, and you get ballistic
electrons and a quantum surprise". New Scientist. 1887: 30. Retrieved
^ Blackwell, G.R. (2000). The Electronic Packaging Handbook. CRC
Press. pp. 6.39–6.40. ISBN 0-8493-8591-1.
^ Durrant, A. (2000). Quantum
Physics of Matter: The Physical World.
CRC Press. pp. 43, 71–78. ISBN 0-7503-0721-8.
^ Staff (2008). "The Nobel Prize in
Physics 1972". The Nobel
Foundation. Retrieved 2008-10-13.
^ Kadin, A.M. (2007). "Spatial Structure of the Cooper Pair". Journal
Superconductivity and Novel Magnetism. 20 (4): 285–292.
arXiv:cond-mat/0510279 . doi:10.1007/s10948-006-0198-z.
^ "Discovery About Behavior Of Building Block Of Nature Could Lead To
Computer Revolution". ScienceDaily. July 31, 2009. Retrieved
^ Jompol, Y.; et al. (2009). "Probing Spin-Charge Separation in a
Tomonaga-Luttinger Liquid". Science. 325 (5940): 597–601.
arXiv:1002.2782 . Bibcode:2009Sci...325..597J.
doi:10.1126/science.1171769. PMID 19644117.
^ Staff (2008). "The Nobel Prize in
Physics 1958, for the discovery
and the interpretation of the Cherenkov effect". The Nobel Foundation.
^ Staff (August 26, 2008). "
Special Relativity". Stanford Linear
Accelerator Center. Retrieved 2008-09-25.
^ Adams, S. (2000). Frontiers: Twentieth Century Physics. CRC Press.
p. 215. ISBN 0-7484-0840-1.
^ Lurquin, P. F. (2003). The Origins of Life and the Universe.
Columbia University Press. p. 2. ISBN 0-231-12655-7.
^ Silk, J. (2000). The Big Bang: The Creation and Evolution of the
Universe (3rd ed.). Macmillan. pp. 110–112, 134–137.
^ Kolb, E. W.; Wolfram, Stephen (1980). "The Development of Baryon
Asymmetry in the Early Universe".
Physics Letters B. 91 (2):
^ Sather, E. (Spring–Summer 1996). "The Mystery of Matter Asymmetry"
(PDF). Beam Line. University of Stanford. Retrieved 2008-11-01.
^ Burles, S.; Nollett, K. M.; Turner, M. S. (1999). "Big-Bang
Nucleosynthesis: Linking Inner Space and Outer Space".
^ Boesgaard, A. M.; Steigman, G. (1985). "Big bang
nucleosynthesis – Theories and observations". Annual Review of
Astronomy and Astrophysics. 23 (2): 319–378.
^ a b Barkana, R. (2006). "The First Stars in the Universe and Cosmic
Reionization". Science. 313 (5789): 931–934.
arXiv:astro-ph/0608450 . Bibcode:2006Sci...313..931B.
doi:10.1126/science.1125644. PMID 16917052.
^ Burbidge, E. M.; et al. (1957). "Synthesis of Elements in Stars".
Reviews of Modern Physics. 29 (4): 548–647.
^ Rodberg, L. S.; Weisskopf, V. (1957). "Fall of Parity: Recent
Discoveries Related to Symmetry of Laws of Nature". Science. 125
(3249): 627–633. Bibcode:1957Sci...125..627R.
doi:10.1126/science.125.3249.627. PMID 17810563.
^ Fryer, C. L. (1999). "Mass Limits For Black Hole Formation". The
Astrophysical Journal. 522 (1): 413–418. arXiv:astro-ph/9902315 .
^ Parikh, M. K.; Wilczek, F. (2000). "Hawking Radiation As Tunneling".
Physical Review Letters. 85 (24): 5042–5045.
arXiv:hep-th/9907001 . Bibcode:2000PhRvL..85.5042P.
doi:10.1103/PhysRevLett.85.5042. PMID 11102182.
^ Hawking, S. W. (1974). "
Black hole explosions?". Nature. 248 (5443):
30–31. Bibcode:1974Natur.248...30H. doi:10.1038/248030a0.
^ Halzen, F.; Hooper, D. (2002). "High-energy neutrino astronomy: the
cosmic ray connection". Reports on Progress in Physics. 66 (7):
1025–1078. arXiv:astro-ph/0204527 . Bibcode:2002RPPh...65.1025H.
^ Ziegler, J. F. (1998). "Terrestrial cosmic ray intensities". IBM
Journal of Research and Development. 42 (1): 117–139.
^ Sutton, C. (August 4, 1990). "Muons, pions and other strange
particles". New Scientist. Retrieved 2008-08-28.
^ Wolpert, S. (July 24, 2008). "Scientists solve 30-year-old aurora
borealis mystery". University of California. Archived from the
original on August 17, 2008. Retrieved 2008-10-11.
^ Gurnett, D.A.; Anderson, R. (1976). "
Electron Plasma Oscillations
Associated with Type III Radio Bursts". Science. 194 (4270):
doi:10.1126/science.194.4270.1159. PMID 17790910.
^ Martin, W.C.; Wiese, W.L. (2007). "Atomic Spectroscopy: A Compendium
of Basic Ideas, Notation, Data, and Formulas". National Institute of
Standards and Technology. Retrieved 2007-01-08.
^ Fowles, G.R. (1989). Introduction to Modern Optics. Courier Dover.
pp. 227–233. ISBN 0-486-65957-7.
^ Staff (2008). "The Nobel Prize in
Physics 1989". The Nobel
Foundation. Retrieved 2008-09-24.
^ Ekstrom, P.; Wineland, David (1980). "The isolated Electron" (PDF).
Scientific American. 243 (2): 91–101. Bibcode:1980SciAm.243b.104E.
doi:10.1038/scientificamerican0880-104. Retrieved 2008-09-24.
^ Mauritsson, J. "
Electron filmed for the first time ever" (PDF). Lund
University. Archived from the original (PDF) on March 25, 2009.
^ Mauritsson, J.; et al. (2008). "Coherent
Captured by an
Attosecond Quantum Stroboscope". Physical Review
Letters. 100 (7): 073003. arXiv:0708.1060 .
^ Damascelli, A. (2004). "Probing the Electronic Structure of Complex
Systems by ARPES". Physica Scripta. T109: 61–74.
arXiv:cond-mat/0307085 . Bibcode:2004PhST..109...61D.
^ Staff (April 4, 1975). "Image # L-1975-02972". Langley Research
Center, NASA. Archived from the original on December 7, 2008.
^ Elmer, J. (March 3, 2008). "Standardizing the Art of Electron-Beam
Welding". Lawrence Livermore National Laboratory. Retrieved
^ Schultz, H. (1993).
Electron Beam Welding. Woodhead Publishing.
pp. 2–3. ISBN 1-85573-050-2.
^ Benedict, G.F. (1987). Nontraditional Manufacturing Processes.
Manufacturing engineering and materials processing. 19. CRC Press.
p. 273. ISBN 0-8247-7352-7.
^ Ozdemir, F.S. (June 25–27, 1979).
Electron beam lithography.
Proceedings of the 16th Conference on Design automation. San Diego,
IEEE Press. pp. 383–391. Retrieved 2008-10-16.
^ Madou, M.J. (2002). Fundamentals of Microfabrication: the Science of
Miniaturization (2nd ed.). CRC Press. pp. 53–54.
^ Jongen, Y.; Herer, A. (May 2–5, 1996).
Electron Beam Scanning in
Industrial Applications. APS/AAPT Joint Meeting. American Physical
^ Mobus, G.; et al. (2010). "Nano-scale quasi-melting of
alkali-borosilicate glasses under electron irradiation". Journal of
Nuclear Materials. 396 (2–3): 264–271.
doi:10.1016/j.jnucmat.2009.11.020. CS1 maint: Explicit use of et
^ Beddar, A.S.; Domanovic, Mary Ann; Kubu, Mary Lou; Ellis, Rod J.;
Sibata, Claudio H.; Kinsella, Timothy J. (2001). "Mobile linear
accelerators for intraoperative radiation therapy". AORN Journal. 74
(5): 700–705. doi:10.1016/S0001-2092(06)61769-9.
^ Gazda, M.J.; Coia, L.R. (June 1, 2007). "Principles of Radiation
Therapy" (PDF). Retrieved 2013-10-31.
^ Chao, A.W.; Tigner, M. (1999). Handbook of Accelerator
Engineering. World Scientific. pp. 155, 188.
^ Oura, K.; et al. (2003). Surface Science: An Introduction. Springer.
pp. 1–45. ISBN 3-540-00545-5.
^ Ichimiya, A.; Cohen, P.I. (2004). Reflection High-energy Electron
Diffraction. Cambridge University Press. p. 1.
^ Heppell, T.A. (1967). "A combined low energy and reflection high
energy electron diffraction apparatus". Journal of Scientific
Instruments. 44 (9): 686–688. Bibcode:1967JScI...44..686H.
^ McMullan, D. (1993). "Scanning
Electron Microscopy: 1928–1965".
University of Cambridge. Retrieved 2009-03-23.
^ Slayter, H.S. (1992).
Light and electron microscopy. Cambridge
University Press. p. 1. ISBN 0-521-33948-0.
^ Cember, H. (1996). Introduction to Health Physics. McGraw-Hill
Professional. pp. 42–43. ISBN 0-07-105461-8.
^ Erni, R.; et al. (2009). "Atomic-Resolution Imaging with a Sub-50-pm
Physical Review Letters. 102 (9): 096101.
^ Bozzola, J.J.; Russell, L.D. (1999).
Electron Microscopy: Principles
and Techniques for Biologists. Jones & Bartlett Publishers.
pp. 12, 197–199. ISBN 0-7637-0192-0.
^ Flegler, S.L.; Heckman Jr., J.W.; Klomparens, K.L. (1995). Scanning
Electron Microscopy: An Introduction (Reprint ed.).
Oxford University Press. pp. 43–45.
^ Bozzola, J.J.; Russell, L.D. (1999).
Electron Microscopy: Principles
and Techniques for Biologists (2nd ed.). Jones & Bartlett
Publishers. p. 9. ISBN 0-7637-0192-0.
^ Freund, H.P.; Antonsen, T. (1996). Principles of Free-Electron
Lasers. Springer. pp. 1–30. ISBN 0-412-72540-1.
^ Kitzmiller, J.W. (1995). Television Picture Tubes and Other
Cathode-Ray Tubes: Industry and Trade Summary. DIANE Publishing.
pp. 3–5. ISBN 0-7881-2100-6.
^ Sclater, N. (1999). Electronic Technology Handbook. McGraw-Hill
Professional. pp. 227–228. ISBN 0-07-058048-0.
^ Staff (2008). "The History of the Integrated Circuit". The Nobel
Foundation. Retrieved 2008-10-18.
Wikiquote has quotations related to: Electron
Wikisource has the text of the 1911 Encyclopædia Britannica article
Wikimedia Commons has media related to Electrons.
"The Discovery of the Electron". American Institute of Physics, Center
for History of Physics.
Particle Data Group". University of California.
Bock, R.K.; Vasilescu, A. (1998). The
Particle Detector BriefBook
(14th ed.). Springer. ISBN 3-540-64120-3.
Copeland, Ed. "Spherical Electron". Sixty Symbols.
Brady Haran for the
University of Nottingham.
Anomalous magnetic dipole moment
Particles in physics
W and Z bosons
Sfermion (Stop squark)
W′ and Z′ bosons
X and Y bosons
Baryons / hyperons
Mesons / quarkonia
Eta and eta prime mesons
Timeline of particle discoveries
History of subatomic physics
Particles of the Standard Model