MцІssbauer (Mossbauer), Rudolf L.

genus. January 31, 1929
The German physicist Rudolf MцІssbauer was born in Munich and was one of two children and only son of Ludwig Mossbauer, photographic equipment, and Erna (nee Ernst) MцІssbauer. Receiving primary education in local schools, he joined then non-classical secondary school in Munich, where he graduated in 1948. For a time he worked in an optical company, then entered the Technical University of Munich, in 1952. earn a BA in 1955. - Master, and in 1958. - Dr.. During the 1953/54 academic r. worked as a teacher of mathematics at the same university. From 1955 to 1957. He was an assistant at the Institute of Medical Research in Heidelberg, was part of the Max Planck Institute, and in 1958. was Research Fellow at Munich University of Technology.
. Doctoral research Moscow, though, and were mainly in the Max Planck Institute, have been implemented under the guidance of his supervisor, a physicist from Munich, Heinz Maier-Leibnitz
. These studies were the emission and absorption of gamma rays by atomic nuclei. Gamma-rays - a type of electromagnetic radiation, whose energy exceeds the energy of X-rays are emitted by unstable (radioactive) nuclei.
Since 1850. it was known that some gases, liquids and solids (eg fluorochemical) absorb electromagnetic radiation (usually visible light) and immediately re-emit it (this phenomenon is called fluorescence). In the special case, known as resonance fluorescence, and the absorbed and emitted radiation have the same energy, wavelength and frequency. Important information about the structure of atoms was obtained by using a similar phenomenon of fluorescence X-rays, in which the material, excited by absorption of X-rays, emits X-rays of the same wavelength and frequency. Fluorescence X-rays were detected and measured between 1915 and 1925. Charles Barkley and Kai Sigbanom.
Fluorescence absorption occurs only if the energy of exciting photons (particles of electromagnetic radiation) is equal to the energy required to excite an atom or its nucleus. However, the photon energy depends on the atomic motion, which it absorbs or emits: the atom and the photon is close to one another - energy increases, but if they are removed from each other - the energy decreases. This complicates the picture, because the phenomenon of radiation or absorption of a photon is determined by its movement on the atom.
. The process of emission or absorption of a photon takes place with preservation of both energy and momentum in other words, the total energy and total momentum of the photon and the atom must remain the same before and after the event
. It follows that, emitting a photon, the atom must be feeling the impact. The energy of the impact of such subtracted from the photon energy, which, therefore, becomes somewhat less than the energy that would have a photon, if such a return was not.
. For visible light photons, which have relatively low energy and momentum, the effect of atomic recoil can be neglected
. At the same time, the gamma-ray photons have energies greater than 10 thousand. to one million times the energy of visible light, and the impact becomes significant. When the nucleus emits a photon, the resulting recoil motion of the nucleus causes a marked decrease in the photon energy. As a result, the emitted photon has not quite the same energy (or wavelength, or frequency) that the photon, which can be absorbed in this kind of kernel. For this reason, fluorescence resonance - at which the emitted and absorbed photons must have equal power - typically in the gamma-rays is not observed.
M. found a way to achieve the resonance fluorescence of gamma-rays. As their source, he used the atoms of a radioactive isotope of the metal iridium. Iridium has the form of a crystalline solid, so that both emitting and absorbing atoms occupy a fixed position in the crystals. After cooling the crystals in liquid nitrogen, he was surprised to find that the fluorescence markedly increased. Studying this phenomenon, he found that the individual nuclei, emit or absorb the gamma rays that transmit impulses directly to the interaction of the entire crystal. Since the crystal is much more massive than the core, the emitting and absorbing photons of frequency shift is observed. This phenomenon, which M. called the 'elastic nuclear resonance absorption of gamma radiation', now bears the name of the Mossbauer effect. Like any effect, occurring in a solid, it depends on the crystal structure of matter, temperature and even the presence of minute impurities. M. showed, . that the suppression of nuclear recoil with the help of the Mossbauer effect allows the generation of gamma-rays, . wavelength which is constant to within one billionth (109), other researchers have improved this result, . achieving stability with an accuracy of up to one hundred trillion (1014).,
. First results of the MA, published in 1958, scientists were either ignored or been questioned
. But a year later, recognizing the potential importance of the Mossbauer effect, some of them have repeated his experiments, and the results confirmed. Fact, . that elastic nuclear resonant absorption makes it possible to measure very small differences in energy between the two systems (if only it was large enough, . to prevent the resonance fluorescence), . leads to the method, . having a number of important applications,
. With exceptionally stable wavelength and the frequency fluorescent gamma-rays are used as an extremely accurate tool for measuring the gravitational, electric and magnetic fields of small particles.
. One of the first applications of the Mossbauer effect was in 1959
. Work RV. Pound and GA. Rebka of Harvard University, who used this effect to confirm the predictions of Albert Einstein, that gravitational field can alter the frequency of electromagnetic radiation. Measuring the change in frequency of gamma rays caused by the difference of the gravitational field at the bottom and top of the 70-foot tower, fully confirmed the general theory of relativity Einstein. Mossbauer effect can also obtain information on the magnetic and electrical properties of nuclei and their surrounding electrons. This effect finds application in areas as diverse as archeology, chemical catalysis, molecular structure, valence, solid state physics, nuclear physics and biological polymers.
In 1961. M. received half the Nobel Prize in Physics 'for the study of resonant absorption of gamma radiation and the discovery in this regard, the effect named after him'. Using the Mossbauer effect, "said Aivars Waller, a member of the Royal Swedish Academy of Sciences, at the presentation of the winner, 'it became possible to investigate such important phenomena that were previously out of reach for even the most precise measurements."
. M
. was to become a full professor at Technical University of Munich, but became disillusioned with the bureaucratic and authoritarian principles of organizational structures Germanic universities took in 1960. sabbatical in Heidelberg and became a Research Fellow at Caltech, and the following year became professor of. However, in 1964. He returned to Germany, where he was appointed professor of the Physics Department Technical University of Munich, converting it to model organizational structures of American Universities. Some scientists jokingly called this change in the structure of germanskogo academic education 'second Mossbauer effect'. From 1972 to 1977. M. head of the Institute Laue - Langevin in Grenoble (France).
In 1957. M. married Elizabeth Pritts, a specialist in design, they have - a son and two daughters. In his spare time he plays the piano, ride a bike and take pictures.
M. is a member of the American, European and Germany Physical Society, the Indian Academy of Sciences and the American Academy of Arts and Sciences. He was awarded honorary doctorates from Oxford, Leicester and the University of Grenoble. In addition to the Nobel Prize, he received an award for scientific achievement of the American Research Corporation (1960), Prize Roentgen Hesse University (1961) and Elliott Cresson Medal Franklinovskogo Institute (1961).