Fritz London
Encyclopedia
Fritz Wolfgang London was a German theoretical physicist
. 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
, he made a significant contribution to understanding electromagnetic properties of superconductors (see London equations
).
, Germany (now Wrocław, 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 the United States in 1939. In 1945, he became a naturalized citizen. London was in his later life a professor at Duke University
. He was awarded the Lorentz Medal
in 1953. He died in Durham, North Carolina
in 1954.
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 the Pauli 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 1 nanometer) distance from each other. Nowadays this attraction is often referred to as "London force". In 1930 he gave (together with R. Eisenschitz) 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 are fermion
s.
For atoms and nonpolar molecules, the London dispersion force is the only intermolecular force, and is responsible for their existence in liquid and solid
states. For polar molecules, this force is one part of the van der Waals force, along with forces between the permanent molecular dipole moments.
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 of bosons, a phenomenon now known as Bose–Einstein condensation (BEC). Bose
recognized that the statistics of massless photons could also be applied to massive particles; he 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 local gauge invariance (Weyl) in the context of the then new quantum mechanics
.
a distinguished group of lecturers including twenty Nobel laureates. The scientific interests of each lecturer impinge at one or more points upon the various fields of physics and chemistry to which Fritz London contributed. In December 1972, John Bardeen
, two-time winner of the Nobel Prize in Physics, established an endowment fund "to perpetuate the memory of Fritz London, distinguished scientist and member of the Duke faculty from 1939 to the time of his death in 1954, and to promote research and understanding of Physics at Duke University and in the wider scientific community". Specifically the fund is to be used to (1) underwrite the Fritz London Memorial Prize, given in recognition of outstanding contributions in Low Temperature Physics and (2) provide support for the London Memorial Lectures at Duke University.
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
. 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
Heinz London
Heinz London was a German Physicist. He worked with his brother Fritz on superconductivity, discovering the London equations when working in Oxford, at the Clarendon Laboratory; these equations gave a first explanation to the Meissner effect...
, he made a significant contribution to understanding electromagnetic properties of superconductors (see London equations
London equations
The London equations, developed by brothers Fritz and Heinz London in 1935,relate current to electromagnetic fields in and around a superconductor...
).
Biography
London was born in Breslau, SilesiaSilesia
Silesia is a historical region of Central Europe located mostly in Poland, with smaller parts also in the Czech Republic, and Germany.Silesia is rich in mineral and natural resources, and includes several important industrial areas. Silesia's largest city and historical capital is Wrocław...
, Germany (now Wrocław, Poland) in 1900. After Hitler's Nazi Party passed the 1933 racial laws
Law for the Restoration of the Professional Civil Service
The Law for the Restoration of the Professional Civil Service , also known as Civil Service Law, Civil Service Restoration Act, and Law to Re-establish the Civil Service, was a law passed by the National Socialist regime on April 7, 1933, two months after Adolf...
, London lost his position at the University of Berlin
Humboldt University of Berlin
The Humboldt University of Berlin is Berlin's oldest university, founded in 1810 as the University of Berlin by the liberal Prussian educational reformer and linguist Wilhelm von Humboldt, whose university model has strongly influenced other European and Western universities...
. He took visiting positions in England and France, and eventually emigrated to the United States in 1939. In 1945, he became a naturalized citizen. London was in his later life a professor at Duke University
Duke University
Duke University is a private research university located in Durham, North Carolina, United States. Founded by Methodists and Quakers in the present day town of Trinity in 1838, the school moved to Durham in 1892. In 1924, tobacco industrialist James B...
. He was awarded the Lorentz Medal
Lorentz Medal
Lorentz Medal is a prize awarded every four years by the Royal Netherlands Academy of Arts and Sciences. It was established in 1925 on the occasion of the 50th anniversary of the doctorate of Hendrik Lorentz. This solid gold medal is given for important contributions to theoretical physics, though...
in 1953. He died in Durham, North Carolina
Durham, North Carolina
Durham is a city in the U.S. state of North Carolina. It is the county seat of Durham County and also extends into Wake County. It is the fifth-largest city in the state, and the 85th-largest in the United States by population, with 228,330 residents as of the 2010 United States census...
in 1954.
Academic achievements
London's early work with Walter HeitlerWalter Heitler
Walter Heinrich Heitler was a German physicist who made contributions to quantum electrodynamics and quantum field theory...
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
Werner Heisenberg
Werner Karl Heisenberg was a German theoretical physicist who made foundational contributions to quantum mechanics and is best known for asserting the uncertainty principle of quantum theory...
and Schrödinger
Erwin Schrödinger
Erwin Rudolf Josef Alexander Schrödinger was an Austrian physicist and theoretical biologist who was one of the fathers of quantum mechanics, and is famed for a number of important contributions to physics, especially the Schrödinger equation, for which he received the Nobel Prize in Physics in 1933...
, 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 the Pauli 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 1 nanometer) distance from each other. Nowadays this attraction is often referred to as "London force". In 1930 he gave (together with R. Eisenschitz) 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 are fermion
Fermion
In particle physics, a fermion is any particle which obeys the Fermi–Dirac statistics . Fermions contrast with bosons which obey Bose–Einstein statistics....
s.
For atoms and nonpolar molecules, the London dispersion force is the only intermolecular force, and is responsible for their existence in liquid and solid
Solid
Solid is one of the three classical states of matter . It is characterized by structural rigidity and resistance to changes of shape or volume. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire volume available to it like a...
states. For polar molecules, this force is one part of the van der Waals force, along with forces between the permanent molecular dipole moments.
London was the first theoretical physicist to make the fundamental, and at the time controversial, suggestion that superfluidity is intrinsically related to the Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...
condensation of bosons, a phenomenon now known as Bose–Einstein condensation (BEC). Bose
Satyendra Nath Bose
Satyendra Nath Bose FRS was an Indian mathematician and physicist noted for his collaboration with Albert Einstein in developing a theory regarding the gaslike qualities of electromagnetic radiation. He is best known for his work on quantum mechanics in the early 1920s, providing the foundation...
recognized that the statistics of massless photons could also be applied to massive particles; he 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 local gauge invariance (Weyl) in the context of the then new quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
.
Fritz London Memorial Lectures and Prize
Since 1956, the Fritz London Memorial Lectures have brought to the scientific community at Duke UniversityDuke University
Duke University is a private research university located in Durham, North Carolina, United States. Founded by Methodists and Quakers in the present day town of Trinity in 1838, the school moved to Durham in 1892. In 1924, tobacco industrialist James B...
a distinguished group of lecturers including twenty Nobel laureates. The scientific interests of each lecturer impinge at one or more points upon the various fields of physics and chemistry to which Fritz London contributed. In December 1972, John Bardeen
John Bardeen
John Bardeen was an American physicist and electrical engineer, the only person to have won the Nobel Prize in Physics twice: first in 1956 with William Shockley and Walter Brattain for the invention of the transistor; and again in 1972 with Leon Neil Cooper and John Robert Schrieffer for a...
, two-time winner of the Nobel Prize in Physics, established an endowment fund "to perpetuate the memory of Fritz London, distinguished scientist and member of the Duke faculty from 1939 to the time of his death in 1954, and to promote research and understanding of Physics at Duke University and in the wider scientific community". Specifically the fund is to be used to (1) underwrite the Fritz London Memorial Prize, given in recognition of outstanding contributions in Low Temperature Physics and (2) provide support for the London Memorial Lectures at Duke University.
External links
- Article about Fritz London
- Article from Duke Physics Dept.
- Key Participants: Fritz London - Linus Pauling and the Nature of the Chemical Bond: A Documentary History