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Term Symbol
In atomic physics, a term symbol is an abbreviated description of the total spin and orbital angular momentum quantum numbers of the electrons in a multi-electron atom. So while the word ''symbol'' suggests otherwise, it represents an actual ''value'' of a physical quantity. For a given electron configuration of an atom, its state depends also on its total angular momentum, including spin and orbital components, which are specified by the term symbol. The usual atomic term symbols assume angular momentum coupling#LS coupling, LS coupling (also known as Russell–Saunders coupling) in which the all-electron total quantum numbers for orbital (''L''), spin (''S'') and total (''J'') angular momenta are good quantum numbers. In the terminology of atomic spectroscopy, ''L'' and ''S'' together specify a term; ''L'', ''S'', and ''J'' specify a level; and ''L'', ''S'', ''J'' and the magnetic quantum number ''M''''J'' specify a state. The conventional term symbol has the form 2''S''+1''L'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Momentum Coupling
In quantum mechanics, angular momentum coupling is the procedure of constructing eigenstates of total angular momentum out of eigenstates of separate angular momenta. For instance, the orbit and spin of a single particle can interact through spin–orbit interaction, in which case the complete physical picture must include spin–orbit coupling. Or two charged particles, each with a well-defined angular momentum, may interact by Electrostatic#Coulomb's law, Coulomb forces, in which case coupling of the two one-particle angular momenta to a total angular momentum is a useful step in the solution of the two-particle Schrödinger equation. In both cases the separate angular momenta are no longer constants of motion, but the sum of the two angular momenta usually still is. Angular momentum coupling in atoms is of importance in atomic spectroscopy. Angular momentum coupling of electron spins is of importance in quantum chemistry. Also in the nuclear shell model angular momentum co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Physics
Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. Atomic physics typically refers to the study of atomic structure and the interaction between atoms. It is primarily concerned with the way in which electrons are arranged around the nucleus and the processes by which these arrangements change. This comprises ions, neutral atoms and, unless otherwise stated, it can be assumed that the term ''atom'' includes ions. The term ''atomic physics'' can be associated with nuclear power and nuclear weapons, due to the synonymous use of ''atomic'' and ''nuclear'' in standard English. Physicists distinguish between atomic physics—which deals with the atom as a system consisting of a nucleus and electrons—and nuclear physics, which studies nuclear reactions and special properties of atomic nuclei. As with many scientific fields, strict delineation can be highly contrived and atomic physics is often considered in the w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rydberg–Ritz Combination Principle
The Rydberg–Ritz combination principle is an empirical rule proposed by Walther Ritz in 1908 to describe the relationship of the spectral lines for all atoms, as a generalization of an earlier rule by Johannes Rydberg for the hydrogen atom and the alkali metals. The principle states that the spectral lines of any element include frequencies that are either the sum or the difference of the frequencies of two other lines. Lines of the spectra of elements could be predicted from existing lines. Since the frequency of light is proportional to the wavenumber or reciprocal wavelength, the principle can also be expressed in terms of wavenumbers which are the sum or difference of wavenumbers of two other lines. Another related version is that the wavenumber or reciprocal wavelength of each spectral line can be written as the difference of two terms. The simplest example is the hydrogen atom, described by the Rydberg formula :\frac = R\left(\frac-\frac\right) where \lambda is the wave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffuse Series
The diffuse series is a series of spectral lines in the atomic emission spectrum caused when electrons jump between the lowest p orbital and d orbitals of an atom. The total orbital angular momentum changes between 1 and 2. The spectral lines include some in the visible light, and may extend into ultraviolet or near infrared. The lines get closer and closer together as the frequency increases never exceeding the series limit. The diffuse series was important in the development of the understanding of electron shells and subshells in atoms. The diffuse series has given the letter ''d'' to the d atomic orbital or subshell. The diffuse series has values given by v=\frac-\frac \quad\text \;\, m=2,3,4,... The series is caused by transitions from the lowest P state to higher energy D orbitals. One terminology to identify the lines is: 1P-mD But note that 1P just means the lowest P state in the valence shell of an atom and that the modern designation would start at 2P, and is large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Principal Series (spectroscopy)
In atomic emission spectroscopy, the principal series is a series of spectral lines caused when electrons move between p orbitals of an atom and the lowest available s orbital. These lines are usually found in the visible and ultraviolet portions of the electromagnetic spectrum. The principal series has given the letter ''p'' to the p atomic orbital and subshell. The lines are absorption lines when the electron gains energy from an s subshell to a p subshell. When electrons descend in energy they produce an emission spectrum. The term principal came about because this series of lines is observed both in absorption and emission for alkali metal vapours. Other series of lines appear in the emission spectrum only and not in the absorption spectrum, and were named the sharp series and the diffuse series The diffuse series is a series of spectral lines in the atomic emission spectrum caused when electrons jump between the lowest p orbital and d orbitals of an atom. The total orbita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sharp Series
The sharp series is a series of spectral lines in the atomic emission spectrum caused when electrons descend from higher-energy s orbitals of an atom to the lowest available p orbital. The spectral lines include some in the visible light, and they extend into the ultraviolet. The lines get closer and closer together as the frequency increases never exceeding the series limit. The sharp series was important in the development of the understanding of electron shells and subshells in atoms. The sharp series has given the letter ''s'' to the s atomic orbital or subshell. The sharp series has a limit given by v=\frac-\frac \text m=2,3,4,5,6,... The series is caused by transitions to the lowest P state from higher energy S orbitals. One terminology to identify the lines is: 1P-mS But note that 1P just means the lowest P state in an atom and that the modern designation would start at 2P, and is larger for higher atomic numbered atoms. The terms can have different designations, mS for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azimuthal Quantum Number
In quantum mechanics, the azimuthal quantum number is a quantum number for an atomic orbital that determines its angular momentum operator, orbital angular momentum and describes aspects of the angular shape of the orbital. The azimuthal quantum number is the second of a set of quantum numbers that describe the unique quantum state of an electron (the others being the principal quantum number , the magnetic quantum number , and the spin quantum number ). For a given value of the principal quantum number (''electron shell''), the possible values of are the integers from 0 to . For instance, the shell has only orbitals with \ell=0, and the shell has only orbitals with \ell=0, and \ell=1. For a given value of the azimuthal quantum number , the possible values of the magnetic quantum number are the integers from to , including 0. In addition, the spin quantum number can take two distinct values. The set of orbitals associated with a particular value of are som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Angular Momentum Quantum Number
In quantum mechanics, the total angular momentum quantum number parametrises the total angular momentum of a given particle, by combining its orbital angular momentum and its intrinsic angular momentum (i.e., its spin). If s is the particle's spin angular momentum and ℓ its orbital angular momentum vector, the total angular momentum j is \mathbf j = \mathbf s + \boldsymbol ~. The associated quantum number is the main total angular momentum quantum number ''j''. It can take the following range of values, jumping only in integer steps: \vert \ell - s\vert \le j \le \ell + s where ''ℓ'' is the azimuthal quantum number (parameterizing the orbital angular momentum) and ''s'' is the spin quantum number (parameterizing the spin). The relation between the total angular momentum vector j and the total angular momentum quantum number ''j'' is given by the usual relation (see angular momentum quantum number) \Vert \mathbf j \Vert = \sqrt \, \hbar The vector's ''z''-projection is giv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiplicity (chemistry)
In spectroscopy and quantum chemistry, the multiplicity of an energy level is defined as ''2S+1'', where ''S'' is the total spin angular momentum. States with multiplicity 1, 2, 3, 4, 5 are respectively called singlets, doublets, triplets, quartets and quintets. In the ground state of an atom or molecule, the unpaired electrons usually all have parallel spin. In this case the multiplicity is also equal to the number of unpaired electrons plus one. Atoms The multiplicity is often equal to the number of possible orientations of the total spin relative to the total orbital angular momentum ''L'', and therefore to the number of near– degenerate levels that differ only in their spin–orbit interaction energy. For example, the ground state of a carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spin Quantum Number
In physics and chemistry, the spin quantum number is a quantum number (designated ) that describes the intrinsic angular momentum (or spin angular momentum, or simply ''spin'') of an electron or other particle. It has the same value for all particles of the same type, such as = for all electrons. It is an integer for all bosons, such as photons, and a half-odd-integer for all fermions, such as electrons and protons. The component of the spin along a specified axis is given by the spin magnetic quantum number, conventionally written . The value of is the component of spin angular momentum, in units of the reduced Planck constant , parallel to a given direction (conventionally labelled the –axis). It can take values ranging from + to − in integer increments. For an electron, can be either or . Nomenclature The phrase ''spin quantum number'' refers to quantized spin angular momentum. The symbol is used for the spin quantum number, and is described as the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
