Gustav Hertz (Hertz)( German physicist, Nobel Prize in Physics, 1925)
Comments for Gustav Hertz (Hertz)
Biography Gustav Hertz (Hertz)
July 22, 1887, Mr.. - October 30, 1975
German physicist Gustav Ludwig Hertz was born in Hamburg in the family lawyer Gustav Hertz and Augusta (Arning) Hertz. His uncle, Rudolf Heinrich Hertz was one of the most eminent physicists of the late XIX century. Received his secondary education in Hamburg Iohanneume, D. in 1906. enrolled in the University of Gottingen, where he studied mathematics and mathematical physics by David Hilbert and Carl Runge. He then studied at the University of Munich at the Arnold Sommerfeld, where he met with the then new quantum theory, and the University of Berlin at the James Franck and Robert Paul. There he became interested in experimental physics. In 1911, Mr.. G. Ph.D. from the University of Berlin on the infrared absorption of carbon dioxide and received his doctorate.
In 1913, Mr.. G. was appointed assistant in the Physics Institute at the University of Berlin, where together with Frank began to study the changes of energy in the collision of an atom with an electron. Their work was a direct confirmation of the correctness of the model of the atom, proposed shortly before Bohr, although they have not been acquainted with her.
. According to the theory of Bohr, the electrons could revolve around the nucleus only 'allowed' orbits, each of which corresponds to a specific energy state of the electron
. According to Bohr, the electron absorbs a quantity of energy, or quantum 'jumps' into orbit, corresponding to higher energy and away from the nucleus. The transition is higher to a lower orbit of an electron emits a quantum. The energy of the quantum is equal to the energy difference between the orbits. Bohr's model will partially explain the mystery before the line spectrum of elements. When the experimenter excites the gas, for example, passing it through an electric discharge, the atoms shed excess energy in the form of radiation - light. The atoms of each element emit light of certain colors, corresponding to a characteristic of the element frequency and wavelength. Spectroscopy makes it possible to separate these frequencies and to obtain a series of colored lines, or line spectrum, characteristic element. Founder of the quantum theory of Max Planck in 1900. showed that the frequency is proportional to the energy of a photon. Thus, according to Bohr's theory, each spectral line corresponds to the energy difference between the two orbits. Thus, line-spectrum serve as a key to the atomic structure.
By applying a positive voltage to the electrode opposite the source of electrons, D. and Frank accelerated electrons (negatively charged particles) in a sealed tube. Electrons, the maximum kinetic energy is known (it is equal to the difference in potential and electron charge) and can be regulated, flying through the rarefied mercury vapor. Another electrode could detect the energy loss of electrons due to collisions with atoms of mercury. It was found that the energy losses are negligible, while the potential difference is less than 4.9 volts. This discovery, showing that the energy is absorbed by an atom only certain portions, confirmed one aspect of Bohr's theory. Similar results were obtained for other gases such as helium and neon. G. and Frank calculated the frequency corresponding to the quantum of energy equal to the electron energy 4.9 electron volt, and found that it coincides with a frequency of one of the lines of the line spectrum of mercury (in the ultraviolet range). But since Bohr's theory at that time 'turned' just a few months and much of it was still unclear, Mr.. and Frank misinterpret 4.9 volts as the ionization potential, ie. as the energy required for ejection of an electron from the atom. Loss of an electron violates the neutrality of the atom - the balance between the negative electrons outside the nucleus and the positive protons in the nucleus - and leads to a positively charged ion. G. and Frank believed that ultraviolet line of mercury emitted in the capture of electrons and ions fill. The main problem was that Bohr's model predicted the ionization potential of 10.36 volts.
. After some confusion, there was a better understanding of the Bohr model, . and then found, . the line, . referred, . consistent electron transition between the two lower orbits in the spectral series, . not the loss of the outer electron and its capture,
. The value of 4.9 volts was not the ionization potential and excitation potential, ie. energy (or quantum) necessary for the excitation of an electron - its transition from one energy level to another, higher, without divorcing it from the atom. By optimizing the experimental technique. , Frank and other researchers measured the number of other (higher) excitation potentials. It was found that the values obtained for the potentials correspond to lines observed in the spectrum of mercury. It was possible to confirm and Bohr predicted value of the ionization potential. G. and Frank were the first physicists who have been directly measure the energy of the quantum.
Later, Frank admitted that they 'do not praise its fundamental importance of Bohr's theory, so that not even mentioned it in his article'. However, Bohr and his associates understand the importance of experiments G. and Frank and repeatedly referred to them in support of their ideas.
In 1926, Mr.. G. and Frank was awarded the Nobel Prize in Physics 1925. 'for the discovery of the laws of collision of an electron with an atom'. Introducing the winners, KV. Oseen from the Royal Swedish Academy of Sciences said: 'Until recently, nobody even thought about, . that the atom can exist in different states, . each of which is characterized by a certain level of energy, . and that these energy levels are determined by the spectral lines ..,
. Bohr's theory put forward this hypothesis, methods of their experimental verification developed G. and James Franck. "
During the First World War, Mr.. and Frank served in the Germany Army. In 1915. G. was seriously wounded. After lengthy treatment he had in 1917. was Visiting Professor at Berlin University. From 1920 to 1925. G. worked in the physics laboratory at the factory lamps firms 'Phillips' in Eindhoven (Netherlands). 'Phillips' was one of the first private companies, financiers fundamental research. In 1925, Mr.. G. became professor of physics at the University of Halle and Director of the Physics Institute at the same university. Three years later, Mr.. returned to Berlin for the post of Director of the Physical Institute at the Technical University Sharlottenburgskom. From the scientific achievements of Mr.. this period the most significant is the development of gas-diffusion method of separation of isotopes of neon.
When in 1933. to power in Germany the Nazis came, Mr.. refused to take an oath of allegiance to Hitler in 1934. was forced to resign. Until the end of the Second World War he worked as director of the Research Laboratory of the firms' Siemens and Halske "in Berlin. It is unclear why G., whose father was a Jew, and his first wife opposed the Nazis, were allowed to occupy such an important post.
After the war, Mr.. appeared in one group of German scientists who were sent to the Soviet Union, under a contract for ten years. During his visit to the United States in 1939. G. told his friends that the level of physical research in America is very high, but he feels that would be more useful in the Soviet Union. G. hoped that his family will join in Soviet society. But GM and other German scientists were isolated by laboratory. In the Soviet Union, Mr.. led research on atomic energy and radar in the laboratory, which was located in Sukhumi. His method of isotope separation, he has improved so much that it became possible to carry out the separation on an industrial scale. In 1955, Mr.. G. returned to Leipzig, where he became a professor at the University of Karl Marx. As Director of the Physics Institute at the University of Leipzig G. supervised the construction of new building of the institute to replace the destroyed during the war. In 1961. G. retired and settled in East Berlin, where he lived for the past 14 years of his life.
In 1919, Mr.. G. married Ellen Dilman. They had two sons, both subsequently became physicists. In 1943, two years after the death of his first wife, he entered into a second marriage with Charlotte Yollass. G. was a reserved man, and his views and hobbies, little is known except that he was quite professional photographer.
In addition to the Nobel Prize G. was awarded numerous honorary awards, including the Max Planck medal Germanskogo Physical Society and the Lenin Prize, the Soviet government. G. was elected a member of the German Academy of Sciences in Berlin and GцTttingen Academy of Sciences and the Academy of Sciences, Hungary, Czechoslovakia and the Soviet Union.