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Fritz London
Fritz Wolfgang London (March 7, 1900 – March 30, 1954) was a German born physicist and professor at Duke University. His fundamental contributions to the theories of chemical bonding and of intermolecular forces (London dispersion forces) are today considered classic and are discussed in standard textbooks of physical chemistry. With his brother Heinz London, he made a significant contribution to understanding electromagnetic properties of superconductors with the London equations and was nominated for the Nobel Prize in Chemistry on five separate occasions. Biography London was born in Breslau, German Empire, Germany (now Wrocław, Poland) as the son of Franz London (1863-1917). Being a Jew, London lost his position at the Humboldt University of Berlin, University of Berlin after Hitler's Nazi Party passed the Law for the Restoration of the Professional Civil Service, 1933 racial laws. He took visiting positions in England and France, and emigrated to the United States in 1939, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Heinz London
Heinz London (Bonn, Germany 7 November 1907 – 3 August 1970) was a German-British physicist. Together with his brother Fritz London he was a pioneer in the field of superconductivity. Biography London was born in Bonn in a liberal Jewish-German family. His father, Franz London, was professor of mathematics at the University of Bonn and his mother, Luise Burger, was the daughter of a prosperous textile manufacturer. His father died of heart failure when Heinz was nine years old. The greatest influence on Heinz's childhood was his older brother Fritz. Throughout their lives the two brothers maintained a close relationship. Heinz followed in his older brother's footsteps, studying physics, but became an experimental physicist instead and obtained his PhD under the famous superconductivity physicist Francis Simon. This connection also gave Heinz the opportunity to leave Nazi Germany. Frederick Lindemann invited Francis Simon to join the Clarendon Laboratory at the University of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Fermion
In particle physics, a fermion is a subatomic particle that follows Fermi–Dirac statistics. Fermions have a half-integer spin (spin 1/2, spin , Spin (physics)#Higher spins, spin , etc.) and obey the Pauli exclusion principle. These particles include all quarks and leptons and all composite particles made of an even and odd, odd number of these, such as all baryons and many atoms and atomic nucleus, nuclei. Fermions differ from bosons, which obey Bose–Einstein statistics. Some fermions are elementary particles (such as electrons), and some are composite particles (such as protons). For example, according to the spin-statistics theorem in Theory of relativity, relativistic quantum field theory, particles with integer Spin (physics), spin are bosons. In contrast, particles with half-integer spin are fermions. In addition to the spin characteristic, fermions have another specific property: they possess conserved baryon or lepton quantum numbers. Therefore, what is usually referr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Nanometer
330px, Different lengths as in respect to the Molecule">molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm), or nanometer (American spelling Despite the various list of dialects of English, English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography, the two most notable variati ...), is a units of measurement, unit of length in the International System of Units (SI), equal to one billionth (short scale) or one thousand million (long scale) of a metre, meter (0.000000001 m) and to 1000 picometres. One nanometre can be expressed in scientific notation as 1 × 10−9 m and as m. History The nanometre was formerly known as the "''millimicrometre''" – or, more commonly, the "''millimicron''" for short – since it is of a micrometre, micrometer. It was often de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Intermolecular Forces
An intermolecular force (IMF; also secondary force) is the force that mediates interaction between molecules, including the electromagnetic forces of attraction or repulsion which act between atoms and other types of neighbouring particles (e.g. atoms or ions). Intermolecular forces are weak relative to intramolecular forces – the forces which hold a molecule together. For example, the covalent bond, involving sharing electron pairs between atoms, is much stronger than the forces present between neighboring molecules. Both sets of forces are essential parts of force fields frequently used in molecular mechanics. The first reference to the nature of microscopic forces is found in Alexis Clairaut's work ''Théorie de la figure de la Terre,'' published in Paris in 1743. Other scientists who have contributed to the investigation of microscopic forces include: Laplace, Gauss, Maxwell, Boltzmann and Pauling. Attractive intermolecular forces are categorized into the following type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Pauli Principle
In quantum mechanics, the Pauli exclusion principle (German: Pauli-Ausschlussprinzip) states that two or more identical particles with half-integer spins (i.e. fermions) cannot simultaneously occupy the same quantum state within a system that obeys the laws of quantum mechanics. This principle was formulated by Austrian physicist Wolfgang Pauli in 1925 for electrons, and later extended to all fermions with his spin–statistics theorem of 1940. In the case of electrons in atoms, the exclusion principle can be stated as follows: in a poly-electron atom it is impossible for any two electrons to have the same two values of ''all'' four of their quantum numbers, which are: ''n'', the principal quantum number; ', the azimuthal quantum number; ''m'', the magnetic quantum number; and ''ms'', the spin quantum number. For example, if two electrons reside in the same orbital, then their values of ''n'', ', and ''m'' are equal. In that case, the two values of ''m''s (spin) pair must be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Covalent Bond
A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding. For many molecules, the sharing of electrons allows each atom to attain the equivalent of a full valence shell, corresponding to a stable electronic configuration. In organic chemistry, covalent bonding is much more common than ionic bonding. Covalent bonding also includes many kinds of interactions, including σ-bonding, π-bonding, metal-to-metal bonding, agostic interactions, bent bonds, three-center two-electron bonds and three-center four-electron bonds. The term "covalence" was introduced by Irving Langmuir in 1919, with Nevil Sidgwick using "co-valent link" in the 1920s. Merriam-Webster dates the specific phrase ''covalent bond'' to 1939, recognizing its first known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Erwin Schrödinger
Erwin Rudolf Josef Alexander Schrödinger ( ; ; 12 August 1887 – 4 January 1961), sometimes written as or , was an Austrian-Irish theoretical physicist who developed fundamental results in quantum field theory, quantum theory. In particular, he is recognized for postulating the Schrödinger equation, an equation that provides a way to calculate the wave function of a system and how it changes dynamically in time. Schrödinger coined the term "quantum entanglement" in 1935. In addition, he wrote many works on various aspects of physics: statistical mechanics and thermodynamics, physics of dielectrics, color theory, electrodynamics, general relativity, and cosmology, and he made several attempts to construct a unified field theory. In his book ''What Is Life?'' Schrödinger addressed the problems of genetics, looking at the phenomenon of life from the point of view of physics. He also paid great attention to the philosophical aspects of science, ancient, and oriental philoso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Werner Heisenberg
Werner Karl Heisenberg (; ; 5 December 1901 – 1 February 1976) was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics and a principal scientist in the German nuclear program during World War II. He published his Umdeutung paper, ''Umdeutung'' paper in 1925, a major reinterpretation of old quantum theory. In the subsequent series of papers with Max Born and Pascual Jordan, during the same year, his matrix mechanics, matrix formulation of quantum mechanics was substantially elaborated. He is known for the uncertainty principle, which he published in 1927. Heisenberg was awarded the 1932 Nobel Prize in Physics "for the creation of quantum mechanics". Heisenberg also made contributions to the theories of the Fluid dynamics, hydrodynamics of turbulent flows, the atomic nucleus, ferromagnetism, cosmic rays, and subatomic particles. He introduced the concept of a wave function collapse. He was also instrumental in planning the first West Germa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Walter Heitler
Walter Heinrich Heitler (; 2 January 1904 – 15 November 1981) was a German physicist who made contributions to quantum electrodynamics and quantum field theory. He brought chemistry under quantum mechanics through his theory of valence bonding. Education In 1922, Heitler began his study of physics at the Karlsruhe Technische Hochschule, in 1923 at the Humboldt University of Berlin, and in 1924 at the Ludwig Maximilian University of Munich (LMU), where he studied under both Arnold Sommerfeld and Karl Herzfeld. The latter was his thesis advisor when he obtained his doctorate in 1926; Herzfeld taught courses in theoretical physics and one in physical chemistry, and in Sommerfeld's absence often took over his classes. From 1926 to 1927, he was a Rockefeller Foundation Fellow for postgraduate research with Niels Bohr at the Institute for Theoretical Physics at the University of Copenhagen and with Erwin Schrödinger at the University of Zurich. He then became an assistant to Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Naturalized Citizen
Naturalization (or naturalisation) is the legal act or process by which a non-national of a country acquires the nationality of that country after birth. The definition of naturalization by the International Organization for Migration of the United Nations excludes citizenship that is automatically acquired (e.g. at birth) or is acquired by declaration. Naturalization usually involves an application or a motion and approval by legal authorities. The rules of naturalization vary from country to country but typically include a promise to obey and uphold that country's laws and taking and subscribing to an oath of allegiance, and may specify other requirements such as a minimum legal residency and adequate knowledge of the national dominant language or culture. To counter multiple citizenship, some countries require that applicants for naturalization renounce any other citizenship that they currently hold, but whether this renunciation actually causes loss of original citizen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
