GAN (Hahn), Otto

March 8, 1879, Mr.. - July 28, 1968
The German chemist Otto Hahn was born in Frankfurt and was one of three sons, Henry, Ghana, glazier, and Charlotte Giese (nee Shtutsman) Gan, who had another son from his first marriage. After completion of primary education in Klingerskom realschule G. at the request of parents who wanted him to become an architect and enrolled at the Technical University. Convinced that he likes chemistry, he was transferred to the University of Marburg. One year later he moved to the University of Munich on the profile of physical and inorganic chemistry, zoology and art. For his doctorate he returned to Marburg, where in 1901. and receives the desired degree of. After a year of military service in 81 th Infantry Regiment in Frankfurt, he returned to academic work, becoming an assistant lecturer at the University of Marburg.
. To improve the English language, in which he needed to obtain positions in industry, Mr.
. spent part of 1904,. in the laboratory of William Ramsay at University College London. Receiving the task to provide pure radium from the ore of barium carbonate, D. opened up new pieces of radioactive chemical element thorium, one of whom he described radiothorium. Young chemist made a favorable impression on Ramsay, and he recommended it to Emil Fischer, director of the Chemical Institute at the University of Berlin. Fisher agreed to accept Mr.. to work immediately after his return from Canada, where in Montreal at McGill University he spent six months under the guidance of Ernest Rutherford conducted research on radioactivity.
The fact that U.G. Bragg discovered that a set of alpha particles emitted by radioactive atoms, which is characteristic for each atom. At McGill G. measured a set of alpha-particles for drug radiothorium and as a result opened a new radioactive substance with a high-energy alpha particles. This element, which he called thorium-C, had a very low life expectancy and could not be chemically separated from radiothorium. Now known as polonium-214, he had the half-life (time during which the substance is carried out half-life), equal to a three million share of a second. In the study of polonium-214, F. described the properties radioactinium.
Upon his return to Germany, Mr.. continued his studies with radioactive elements in the Chemistry Institute. Here, he confirmed the existence of intermediate radioactive substance mesothorium. In 1907, Mr.. Lise Meitner, a physicist from Vienna, arrived in Berlin to study and carry out experimental work at the Max Planck. Although women were forbidden to work with male students in one lab, she was allowed to visit the laboratory of Mr.. Cooperation,. Meitner and lasted more than 30 years. They studied the problem of emission of electrons from radioactive nuclei (beta decay) and identified several previously unknown radioactive products obtained in the process of transformation. When in 1912. created the Institute of Physical Chemistry and Electrochemistry, Kaiser Wilhelm, F. became director of the radiochemical. Institute's equipment allowed Mr.. Meitner and to work on the study of rubidium and potassium - common elements in nature with weak radioactivity. Defining a half-time of rubidium, which was equal to 230 billion years, T. showed that age rubidiysoderzhaschih minerals can be calculated based on the analysis of the decay of rubidium to turn it into strontium.
At the beginning of World War H. was drafted into the infantry regiment of the army, took part in the fighting on the Western Front was awarded the. But since he was a chemist, he is transferred to the service involved in the creation of chemical weapons, where he worked under the guidance of Fritz Haber, who dispelled the initial doubts Mr.. against these weapons, convincing him that such an instrument would lead to more rapid conclusion of the war and thus save many lives. G. several times participated in the preparation of gas attacks, and experienced the stress of the observed effect. Just moved to Berlin in 1917, Mr.. able to resume his work with the Meitner on the decay of radioactive substances at this time he finds an unstable element - protactinium.
Continuing post-war study of radioactivity, D. noticed that many of the radioactive substance, apparently, have the same chemical properties. This phenomenon has been explained in the work of British scientists Frederick Soddy, J. Thomson and Francis I. Aston, who found that the isotopes of the element in the kernel have a different number of neutrons, which are responsible for the change of nuclear properties and behavior. G. discovered uranium-Z, which was the first example of the existence of isomers of radioactive atoms. Then he was interested in aspects of the application of radioisotopes in chemistry, including the formation of crystals and the use of labeled atoms in chemical reactions.
In 1928, Mr.. G. was appointed director of the Institute of Physical Chemistry and Electrochemistry of Kaiser Wilhelm. In 1933. He visited the United States of America and made a presentation on the readings on the George Fischer at Cornell University. Hearing that on the basis of the laws of the Nazi scientists of Jewish origin expelled from the Kaiser Wilhelm Institute, and that Haber in protest, resigned, Mr.. hurried back to Germany. The following year he took part in a conference on Haber after his death in Switzerland. Despite the failure of Mr.. to join the Nazi party, he was allowed to stay in the institute in their respective positions.
In 1934, Mr.. G. with Meitner and joined them a year later, Fritz Strassmann began to study the effect of neutron irradiation of uranium and thorium, assuming that they will form new, heavier than uranium, elements. Even before that, as this group of researchers was able to test this hypothesis, Austria was occupied by Germany, and Meitner, who was an Austrian Jew, fled to Sweden. Based in Stockholm, Meitner, together with her nephew Otto Frisch, also a physicist, continued joint research with AG, corresponding by e-mail. To everyone's surprise, they discovered that the bombardment of uranium with neutrons leads to the formation of radioactive substances that are chemically identical to barium, lanthanum and tseriyu. Because these elements have atomic weight twice smaller than the source of uranium, it became clear that neutron irradiation of uranium nucleus splits. Soon it was discovered that in the process, which they called nuclear fission, as well as in a chain reaction, a large amount of energy.
. As the country's anti-Hitler coalition, Germany had a particular interest in using the process of nuclear fission to strengthen its military potential, and soon after the outbreak of World War II Wehrmacht creates a nuclear research center
. G. was connected to these projects, although it had only the fundamental problems for the Study of products of nuclear fission. At the end of the war the Kaiser Wilhelm Institute were destroyed by Allied bombing and moved to r. Taylfingen south Germany. Here, after the occupation of his French troops r. and his colleagues were arrested by the Anglo-American spetsrazvedkoy, shipped to England and questioned about their scientific activities during the war. Few months later, Mr.. suffered a severe shock to learn that the United States in 1945. use nuclear weapons against Japanese cities of Hiroshima and Nagasaki.
While interned in England, Mr.. learns that he was awarded the Nobel Prize in Chemistry for 1944. 'for the discovery of fission of heavy nuclei'. He was allowed to return to Germany in 1946, at the end of that same year he was awarded the Nobel Prize in Stockholm. In his speech at the presentation of the laureate Arne Tizelius, . Member of the Royal Swedish Academy of Sciences, . said: 'The opening of the splitting of heavy nuclei has led to such effects, . that we, . humanity, . look forward with great expectations, . but also with great fear for our future '.,
. In his Nobel lecture Mr.
. followed the path traversed by research from the natural transmutation of uranium, open Antoine Henri Becquerel, for nuclear fission. In conclusion, he quoted a passage from a lecture Frederic Joliot-Curie, he delivered his acceptance in 1935. Nobel Prize, in which the French physicist warned of the grave danger of nuclear energy. "The fact that ten years ago was the fruit of the imagination, 'delusional imagination', today has become somewhat threatening reality '. Turning to the audience and answering the question of whether to use nuclear energy for peaceful purposes or for destruction, Mr.. said: 'The answer should be given without hesitation, that, undoubtedly, the world's scientists will make every effort to win the first alternative. "
In 1946, Mr.. G. became president of the Kaiser Wilhelm Society, renamed the Max Planck Society. He devoted much attention to the reorganization germanskogo scientific community. Speaking with public warnings about the dangers posed by the atomic bomb, he consolidated many physicists, fears the consequences of improving the weapons. In 1959, Mr.. its 80-year anniversary, it was announced that the Institute of Nuclear Research in Berlin, will be renamed the Institute name Ghana - Meitner and Max Planck Institute for Chemistry in Mainz will be the Institute of Otto Hahn. A year later, Mr.. resigned from his post as President of the Max Planck Society.
In 1913, Mr.. G. Yunghans married Edith, daughter of the chairman Shtettinskogo City Council. They had an only son. Shortly after retirement, when he was 811 odes, his son and daughter were killed in France in an automobile accident, and he cared for his wife, who by that time become invalid, and his grandson. G. died July 28, 1968, Mr.. after the fall, leading to a change in the cervical spine.
Among the many honorary awards r. received a medal of Emil Fischer Germanskogo Chemical Society (1922), . Stanislao Cannizzaro prize of the Royal Academy of Sciences in Rome (1938), . Medal of the Max Planck Germanskogo Physical Society (1949), . gold Paracelsus Swiss Chemical Society (1953) and the Faraday Medal of the British Society of Chemistry (1956),
. He was a member of academies around the world, had numerous honorary academic degrees and was an officer of the Legion of Honor of France.