- Fritz London
Infobox Scientist
name = Fritz Wolfgang London
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birth_date =March 7 ,1900
birth_place =Breslau ,Germany
death_date =March 30 ,1954
death_place =Durham, North Carolina
residence =USA
citizenship = German, laterUSA
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field = TheoreticalPhysics
work_institutions = University of Berlin
University of Oxford
College de France
Duke University
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known_for = Work on quantum theory
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prizes =Lorentz Medal , 1953
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footnotes =Fritz Wolfgang London (
March 7 ,1900 –March 30 ,1954 ) was a German-born American theoreticalphysicist . 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 made a significant contribution to understanding electromagnetic properties of superconductors (see
London equations ).Biography
London was born in
Breslau ,Silesia , Germany (now Wroclaw, Poland) in 1900. After Hitler's Nazi Party passed the 1933 racial laws, London lost his position at the University of Berlin. He took visiting positions in England and France, and eventually emigrated to theUnited States in 1939. In 1945, he became anaturalized citizen . London was in his later life a professor atDuke University . He was awarded theLorentz Medal in 1953. He died inDurham, North Carolina in 1954.Academic achievements
London's early work with Heitler [W. Heitler and F. London, Zeitschrift für Physik, vol. 44, p. 455 (1927). English translation in H. Hettema, Quantum Chemistry, Classic Scientific Papers, World Scientific, Singapore (2000). ] on chemical bonding is now treated in any textbook on physical chemistry. This paper was the first to properly explain the bonding in a homonuclear molecule as H2. It is no coincidence that the Heitler-London work appeared shortly after the introduction of quantum mechanics by
Heisenberg and Schrödinger, because quantum mechanics was crucial in their explanation of the covalent bond. Another necessary ingredient was the realization that electrons are indistinguishable, as expressed in thePauli principle .Other early work of London was in the area of
intermolecular forces . He coined the expression "dispersion effect" for the attraction between two rare gas atoms at large (say about 1nanometer ) distance from each other. Nowadays this attraction is often referred to as "London force". In 1930 he gave (together with R. Eisenschitz) [R. Eisenschitz and F. London,Zeitschrift für Physik, vol. 60, p. 491 (1930). English translation in H. Hettema, Quantum Chemistry, Classic Scientific Papers, World Scientific, Singapore (2000).] a unified treatment of the interaction between two noble gas atoms that attract each other at large distance, but at short distance are repellent. Eisenschitz and London showed that this repulsion is a consequence of enforcing the electronic wavefunction to be antisymmetric under electron permutations. This antisymmetry is required by the Pauli principle and the fact that electrons arefermion s.For atoms and
nonpolar molecules, the London dispersion force is the only intermolecular forces and are responsible for the existence of theliquid andsolid states. Forpolar molecules , this force is one part of the van der Waals force, along with forces between the permanent moleculardipole moment s.London was the first theoretical physicist to make the fundamental, and at the time controversial, suggestion that
superfluidity is intrinsically related to the Einstein condensation ofbosons , a phenomenon now known asBose–Einstein condensation (BEC ). However, note thatBose , whose contribution was to recognize that the statistics of massless photons could also be applied to massive particles, did not contribute to the theory of the condensation of bosons.London was also one of the early authors (including
Schrödinger ) to have properly understood the principle of localgauge invariance (Weyl) in the context of the then newquantum mechanics .Bibliography
*Gavroglu, Kostas "Fritz London: A Scientific Biography" (Cambridge, 2005)
References
"Fritz London: A Scientific Biography ", by Kostas Gavroglu, Cambridge University Press (1995). ISBN: 0521432731.
External links
* [http://scienceweek.com/2005/sw051021-1.htm Article about Fritz London]
* [http://www.phy.duke.edu/about/FritzLondon/ Article from Duke Physics Dept.]
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