PAUL (Pauli), Wolfgang( Austrian-Swiss physicist, Nobel Prize in Physics, 1945)
Comments for PAUL (Pauli), Wolfgang
Biography PAUL (Pauli), Wolfgang
April 25, 1890, Mr.. - December 15, 1958
Austrian-Swiss physicist Wolfgang Ernst Pauli was born in Vienna. His father, Wolfgang Joseph Pauli, a famous physicist and a biochemist, a professor of colloid chemistry at the University of Vienna. His mother, Bertha (nee Schutz), Pauli was a writer associated with the Viennese theatrical and journalistic circles. Hertha Berlin, the younger sister of VP, became an actress and writer. Ernst Mach, the famous physicist and philosopher, was his godfather. In high school in Vienna P. demonstrated exceptional mathematical ability, . however, . find classroom boring, . he switched to an independent study of higher mathematics, and so you read the newly published work of Albert Einstein's general theory of relativity.,
. In 1918, Mr.
. P. enrolled in the University of Munich, where he studied under the guidance of the famous physicist Arnold Sommerfeld. At this time, the German mathematician Felix Klein was busy publishing mathematical encyclopedia. Klein asked Sommerfeld write a review of general and special theory of relativity, and Sommerfeld, in turn, asked to write this story to a 20-year-old P. He quickly wrote a volume of 250 pages, which Sommerfeld described as 'just made a masterly', and Einstein praised.
. In 1921, after finishing his doctoral dissertation on the theory of the hydrogen molecule and received his doctoral degree in the shortest time for the university, P
. went to GцІttingen, where he began to research together with Max Born and James Franck. In late 1922. in Copenhagen, he worked as an assistant to Niels Bohr. Work under Sommerfeld, Born, Franck and Bora arouse P. interest in the new field of physics - quantum theory, which has been studying the atom and subatomic particles, and it is fully immersed in the problems faced the physicists in this field.
. While the principles of classical physics allowed to satisfactorily explain the behavior of macroscopic physical systems, attempts to apply the same principles to the phenomena of atomic scale failed
. Especially difficult it is to the nuclear model of the atom, in which electrons revolve in orbits around the central core. According to the principles of classical physics, rotating in their orbits, electrons should continuously emit electromagnetic radiation, losing energy and approaching the spiral to the core. In 1913, Mr.. Bohr suggested that electrons can not continuously emit radiation as they are required to stay in their fixed orbits, all the intermediate orbit is prohibited. Electron can emit or absorb radiation, only making a quantum leap from one allowed orbit to another.
Bohr model partially based on the study of atomic spectra. When an element is heated and turns into gas or vapor state, it emits light with a characteristic spectrum. This spectrum does not represent a continuous field of color, similar to the solar spectrum, but consists of a series of bright lines of certain wavelengths, separated by a wide dark areas. Atomic model of Bohr explained the main essence of atomic spectra: each line represents the light emitted by the atom, where electrons are transferred from one allowed orbit to another orbit with lower energy. Moreover, the model correctly predicted most of the characteristics of the simplest atomic spectrum - the spectrum of hydrogen. At the same time with the help of this model is less successful in describing the spectra of more complex atoms.
Two significant drawbacks Bohr model helped P. continue to make a significant contribution to the quantum theory. First, this model could not explain some of the subtle details of the hydrogen spectrum. For example, when the atomic gas was placed in a magnetic field, some spectral lines are split up into several closely spaced lines - an effect first discovered by Pieter Zeeman in 1896. More important, however, was that the stability of electron orbits could not find a full explanation. While it is obvious, . that electrons could not fall on a spiral into the nucleus, . continuously emitting radiation, . could not see obvious reasons, . why do not they drop jumps, . moving from one allowed orbit to another and coming together in the lowest energy state.,
. In 1923, Mr.
. P. became an assistant professor of theoretical physics at the University of Hamburg. Here he is at the beginning of 1925. engaged in theoretical studies of the structure of atoms and their behavior in magnetic fields, developing the theory of the Zeeman effect and other kinds of spectral splitting. He speculated that the electrons have a certain property, which later Samuel Goudsmit and George Uhlenbeck called spin angular momentum, or own. In a magnetic field at the electron spin has two possible orientations: spin axis can be directed in the same direction as the field or in the opposite direction. The orbital motion of an electron in an atom defines another axis, which can be oriented differently depending on the applied external field. Various possible combinations of spin and orbital orientations are slightly different energy, which leads to an increase in the number of atomic energy states. Transitions of an electron with each of these sublevels to some other orbit correspond to slightly different lengths of light waves, which explains the fine splitting of spectral lines.
Soon after the P. Entered this the 'ambiguity' of the electron, it is analytically explained why all the electrons in an atom does not occupy the lowest energy level. In the improved model of Bohr allowable energy states, or the orbit, the electrons in an atom are described by four quantum numbers for each electron. These numbers determine the basic energy level of the electron, its orbital angular momentum, its magnetic moment and (this was the contribution of AP) orientation of its spin. Each of these quantum numbers can take only certain values, moreover, allowed only certain combinations of data values. He formulated the law, which became known as the Pauli exclusion principle according to which no two electrons in the system may not have the same set of quantum numbers. Thus, each shell in an atom can contain only a limited number of electron orbits determined allowable values of quantum numbers.
. Pauli exclusion principle plays a fundamental role for understanding the structure and behavior of atoms, atomic nuclei, the properties of metals and other physical phenomena
. He explains the chemical interaction of elements and their previously incomprehensible position in the periodic. Sam P. used the principle of the ban in order to understand the magnetic properties of simple metals and some gases.
Soon after the P. articulated the principle of the ban, quantum theory has a solid theoretical foundation through the work of Al-fault SchrцІdinger, Werner Heisenberg and P.A.M. Dirac. Theoretical apparatus used by them to describe the atomic and subatomic systems, became known as quantum mechanics. Bohr's atomic model was replaced by a quantum mechanical model which successfully predicts the spectra and other nuclear phenomena. With regard to the achievements of SP, they are allowed to extend quantum mechanics to such areas as particle physics and high energy particle interactions with light and other forms of electromagnetic fields. These areas became known as relativistic quantum electrodynamics.
In 1928, Mr.. P. Peter Debye was replaced by the post of Professor of the Federal Institute of Technology in Zurich, where he remained until his death, except for two periods, held in the United States, he spent the 1935/36 academic r. as a guest lecturer at the Institute for Basic Research in Princeton (New Jersey), and during the Second World War, . when, . fear, . that Germany would invade Switzerland, . He returned to the same institute, . where he headed the theoretical physics department from 1940 to 1946,
. In 30-ies
. He made another important contribution to physics. Observations of the beta decay of atomic nuclei, . which the neutron in the nucleus emits an electron, . turning to the proton, . revealed a clear violation of the law of conservation of energy: after allowing for all registered products of decomposition after the collapse of the energy is less than its value before the collapse of the,
. In 1930. P. hypothesized, . according to which expected, . that such decay is emitted by some unregistered particle (which Enrico Fermi called the neutrino), . carrying away the lost energy, . while the law of conservation of angular momentum remained in force,
. In the end, neutrinos were able to register in 1956
In 1945, Mr.. P. was awarded the Nobel Prize in Physics "for his discovery of the principle of prohibition, which is also called the Pauli exclusion principle '. He did not attend the award ceremony, and on behalf of the employee has received the American Embassy in Stockholm, Nobel lecture, which was sent to Stockholm next year, P. summarized their work on the principle of prohibition and quantum mechanics.
P. became a Swiss citizen in 1946. In further work, he sought to shed light on the problem of interaction of high energy particles and forces with which they interact, ie. studied an area of physics, which is now called high-energy physics and particle physics. He also conducted a thorough study of the role of particle physics is the symmetry. With a truly fantastic skill and ability to penetrate deeply into the essence of physical problems, he was intolerant to vague arguments and superficial judgments. He exposed their own work to such a merciless critique that his writings actually free from errors. Colleagues called him "the conscience of physics'.
After the divorce that followed the brief and unhappy first marriage, P. in 1934. married Francis Bertram. Feeling a deep interest in philosophy and psychology, he received great pleasure from conversations with his friend K.G. Jung. He also highly valued the arts, music and theater. During the holiday he loved to swim, wander through the mountains and forests of Switzerland. Intellectual ability P. is in sharp dissonance with his 'ability to' work with his hands. His colleagues usually joked about the mysterious 'Pauli effect', when the mere presence of low and stout scientist in the laboratory, it seemed, caused all sorts of breakdowns and accidents. In early December 1958. P. ill and soon, on December 15, has died.
In addition to the Nobel Prize, P. was awarded the Medal of the Franklin Institute Franklinovskogo (1952) and the Max Planck Medal Germanskogo Physical Society (1958). He was a member of the Swiss Physical Society, American Physical Society, American Association for the basic sciences, as well as foreign member of the Royal Society of London.