Van Vleck (Van Vieck), John X.( The American physicist, Nobel Prize in Physics, 1977)
Comments for Van Vleck (Van Vieck), John X.
Biography Van Vleck (Van Vieck), John X.
March 13, 1899, Mr.. October 27, 1980
American physicist John Hazbruk Van Vleck was born in Middletown (Conn.). He was the only child of Edward Burr Van Vleck Professor of Mathematics Veslianskogo University, and Hester Lawrence Van Vleck (nee Raymond). When the boy's father in 1906. moved to the University of Wisconsin, his family moved to Madison, where VF. in high school before joining the University. In 1920, Mr.. He became a Bachelor of Science in the University of Wisconsin, then two years of his postgraduate studies at Harvard University under the guidance P.U. Bridgman and E.K. Kembla. In 1921, Mr.. he became a master, and a year later, the doctor, and in his dissertation, he calculated the binding energy of the helium atom in the model proposed by Kemble and Niels Bohr.
Max Planck introduced the concept of quantum of energy in 1900, but only in 1913. Bohr suggested the beginning of a consistent quantum theory of the atom. This 'old' quantum theory has been superseded in the late 20-ies. quantum mechanics, which has grown from the wave mechanics of Erwin SchrцTdinger and the matrix mechanics of Max Born, Werner Heisenberg and P.A.M. Dirac. In 1926, Mr.. VF. published a 'Quantum principles and line spectra' ( "Quantum Principles and Line Spectra") of the old quantum theory.
After serving postdoctoral lecturer at Harvard University during the year in. F. did work on a physical faculty of the University of Minnesota, where he stayed from 1923 to 1928. Next six years he taught at the University of Wisconsin before returning to Harvard in 1934
Once in 1941. The United States entered World War II, VF. prepared two reports for the Radiation Laboratory at MIT. The following year he received an invitation from Arthur X. Compton to join the Committee for the splitting of uranium at the U.S. National Academy of Sciences, which enabled him to spend the summer at the University of California at Berkeley, where he studied the possibility of nuclear weapons. Upon returning to Harvard in the autumn of that year, he said, but their faculty duties and military research in the university radio laboratory. Thus, during the war, he studied the problems associated with the ratio of signal to noise, and countermeasures to neutralize enemy radars using thin strips of aluminum foil.
By the end of the war in. F. succeeded Kemble, leading the Department of Physics at Harvard University and remained in that post until 1949,. During this time he drew on the faculty of such distinguished physicists as Nicolaas Bloembergen, Edward M. Purcell and Julius C. Schwinger. From 1951 to 1969. V. F. served as professor of mathematics and natural philosophy.
Jobs. F. in 1926, relating to how to use the quantum mechanics can explain the electric and magnetic susceptibility (a measure of the response of matter at the impact of electric and magnetic fields), served as a stage for his later research. His work 'The theory of electric and magnetic susceptibility,' ( "The Theory of Electric and Magnetic Susceptibilities"), . published in 1932, . gives a clear and rigorous description of, . how to apply quantum mechanics to a wide range of phenomena, . occurring in the material volume, . including dielectric constants and ferromagnetism - the type of magnetization, . manifested in conventional magnets,
. This work helped the formation of a new solid-state physics, was used as a textbook for 45 years and brought its author the title "father of modern magnetism."
. Substance with a weak, albeit positive magnetic susceptibility is paramagnetic
. V. F. explained paramagnetism in certain gases and solids, the term 'Van Vleck paramagnetism' means independent of the temperature magnetism manifested in some chemical elements.
Research VF. much has been given to establish the relationships between physics and chemistry through the application of quantum mechanics. He greatly developed the techniques of field theory as applied to the crystals, from which you can calculate the quantum mechanical energy levels of the atom or ion in the crystal. Since the energy levels depend, . particularly, . from the immediate environment of the atom, . they differ from the levels of free atom or ion Precise knowledge of these levels is a prerequisite for understanding the electrical, . magnetic and optical properties of matter; developed methods have been used in the development of lasers and the study of chemical compounds,
. VF. also investigated the properties of paramagnetic at low temperatures, the optical spectra of paramagnetic ions in solids and many other ferromagnetic phenomena.
After the Second World War. F. studied the magnetic resonance, the response of the electron, the nucleus or atom to the electromagnetic radiation. Nuclear magnetic spectroscopy helps to shed light on the structure of molecules. The images obtained using magnetic resonance imaging, have become an important diagnostic tool in medicine. V. F. also studied the binding energy of metals, molecular spectra and ferrimagnetizm (type of magnetism, in which two interpenetrating lattices of magnetic ions are oppositely directed and have varying intensity).
In. F. Philip Y. Anderson and Nevill Mott divided in 1977. Nobel Prize in Physics "for fundamental theoretical investigations of the electronic structure of magnetic and disordered systems'. As said Per-Olof Levdin, a member of the Royal Swedish Academy of Sciences, at the presentation of the winners, work. F. on the electronic structure of magnetic and disordered systems not only signaled a theoretical breakthrough, but also had a 'great importance for the chemistry of complex compounds, Geology, and advanced technology. "
In 1927, Mr.. VF. married Abigail June Pearson; children they did not have VF. was a football fan (preferred football games between Harvard and Yale University), liked to play bridge and listen to classical music. He was known for his extraordinary memory for all sorts of train schedules, interest to which he was born in 1906, when he traveled with his parents in Europe. In addition, he was very fond of walking and hiking trips for days. When Dirac was in Madison in 1929, then with in. F. they long stroll along the outskirts of the city, and in 1931 and in 1934. Both scientists committed hiking trip in the Rocky Mountains. According to Edward Purcell, in. F. 'helped to unite physics and chemistry', not to mention his fundamental contributions to solid state physics. 'He always taught us, went Purcell - calmly, with inexhaustible patience and good will, absolutely, without any hint of haughty condescension'. VF. died of a heart attack at his home in Cambridge (Massachusetts) October 27, 1980
In addition to the Nobel Prize in. F. received the Irving Langmuir Prize in Chemical Physics from the company 'General Electric' (1965), the National Medal 'For his scientific achievements' of the National Science Foundation (1966), the Lorentz Medal of the Royal Netherlands Academy of Arts and Sciences (1974). He was awarded an honorary degree Veslianskogo, Wisconsin, Maryland. Chicago, Oxford and Harvard Universities. He was a member of the American Physical Society (and its president in 1952 ... 1953.), The American Academy of Arts and Sciences, the American National Academy of Sciences. American Philosophical Society and the International Union of Pure and Applied Physics. Of the foreign academies and societies to which he belongs, you can specify the French Academy of Sciences. Netherlands Physical Society and the Royal Society.