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Otto Hahn

Picture of Otto Hahn

Date of Birth: 08/03/1879

Age: 89

Place of birth: Frankfurt

Citizenship: Germany

Background

In order to improve the English language, which he needed for positions in the industrial sector, G. spent part of 1904 in the laboratory of William Ramsay at University College in London. After receiving a task to allocate pure radium from the ore of barium carbonate, G. discovered new radioactive element thorium chemical fragments, one of which he called radiothorium. Young chemist made a favorable impression on Ramsay, and he recommended it to Emil Fischer, Director of the Institute of Chemistry at the University of Berlin. Fischer agreed to G. job immediately after his return from Canada, where at McGill University in Montreal, he spent six months under the supervision of Ernest Rutherford conducted research on radioactivity.

The fact that HS Bragg found that the range of the alpha particles emitted by radioactive atoms, is characteristic of each atom. The McGill University G. measured set of alpha particles for radiothorium drugs and thereby discovered a new radioactive substance with 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 a half-life (time during which the half-life of the substance is carried out), equal to a fraction of a second three million. In addition the study of polonium-214, G. described properties radioaktiniya.

On his return to Germany he continued his studies with radioactive elements in the Chemical Institute. There he confirmed the existence of intermediate radioactive substance mesothorium. In 1907, Lise Meitner, the 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 a lab, she was allowed to visit the laboratory G. Cooperation G. Meitner and lasted more than 30 years. They examined the problem of electron emission from the radioactive nuclei (beta decay) and identified several previously unknown radioactive products obtained in the process of transformation. When in 1912 was created by the Institute of Physical Chemistry and Electrochemistry of Kaiser Wilhelm, he became director of the radiochemical group. The institute`s equipment allowed Mr. Meitner and to work on the study of rubidium and potassium - common elements in nature with weak radioactivity. Having determined the half-life of rubidium, which was equal to 230 billion years, G. showed that age rubidiysoderzhaschih minerals can be calculated on the basis of the analysis of the collapse of the rubidium to convert it into strontium.

At the beginning of the First World War, he was drafted into the infantry regiment of the army, took part in, was awarded the fighting on the Western Front. But because he was a chemist, he was transferred to the service involved in the creation of chemical weapons, where he worked under the direction of Fritz Haber, who dispelled the initial doubts, in relation to these weapons, convincing him that such an instrument would lead to a more rapid conclusion of the war, and thus many will save lives. G. several times participated in the preparation of gas attacks and severe stress experienced by the observed effect. Just moved to Berlin in 1917, G. was able to resume his work with Meitner on the decay of radioactive substances; at this time it detects an unstable element - protactinium.

Continuing after the war, research radioactivity G. noticed that many radioactive substances seem to have the same chemical properties. This phenomenon has been explained in the work of British scientists Frederick Soddy, J.. Thomson and Francis W. Aston, who found that the isotopes of an element are at the core of 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 atoms of radioactive isomer. Then it was interested in aspects of the use of radioisotopes in chemistry, including crystal formation and use of tracer in chemical reactions.

In 1928 he was appointed director of the Institute of Physical Chemistry and Electrochemistry of Kaiser Wilhelm. In 1933 he visited the United States and made a presentation on the readings, dedicated to George Fischer at Cornell University. When he learned that on the basis of the laws of Nazi Jewish scholars expelled from the Kaiser Wilhelm Institute and that Gaber in protest resigned G. hurried back to Germany. The following year he took part in a conference dedicated to Haber after his death in Switzerland. Despite the refusal, he joined the Nazi party, he was allowed to remain at the institute in the former position.

In 1934 GS Meitner and joined them a year later, Fritz Strassmann began to study the effect of neutron irradiation of uranium and thorium, assuming that will form a new, heavier than uranium elements. Even before this group of researchers has been able to test this hypothesis, Austria was annexed by Germany, and Meitner, who was an Austrian Jew, fled to Sweden. Based in Stockholm, Meitner with her nephew Otto Frisch, also a physicist, he continued joint research with H., corresponding by e-mail. To everyone`s surprise, they found that the bombardment of uranium with neutrons leads to the formation of radioactive substances, which are chemically identical to barium, lanthanum and cerium. Since these elements have an atomic weight of less than half that of the original uranium, it became clear that the neutron irradiation of uranium nucleus splits. It was soon discovered that in the process, which they called nuclear fission as well as in a chain reaction, a large amount of energy is released.

Like the anti-Hitler coalition countries, Germany showed a special interest in the use of nuclear decay process to strengthen its military capabilities, and soon after the start of World War II Wehrmacht creates a nuclear research center. G. was connected to these projects, while engaged in a fundamental problem for the study of nuclear fission products. At the end of the war the Kaiser Wilhelm Institute was destroyed by Allied bombing and moved in Taylfingen south Germany. Here, after the occupation of his French troops G. and his colleagues were arrested spetsrazvedkoy Anglo-American, transferred to England and questioned about their research activities during the war. A few months later Mr. suffered a strong shock to learn that the United States in 1945, to use nuclear weapons against the Japanese cities of Hiroshima and Nagasaki.

Having interned in England, G. 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 the same year the Nobel Prize in Stockholm was presented. In his speech at the presentation of the winner Arne Tizelius, a member of the Royal Swedish Academy of Sciences, he said: "The discovery of fission of heavy nuclei has led to such consequences that we, all of humanity, we look forward with high hopes, but also with great concern for our future."

In his Nobel lecture H. followed passed in scientific research by way of natural uranium transmutation open Antoine Henri Becquerel, for nuclear fission. In conclusion, he quoted a passage from the lecture Frederic Joliot-Curie, delivered to them when he received his 1935 Nobel Peace Prize, in which the French physicist warned of the grave danger of nuclear energy. "The fact that ten years ago there was a figment of the imagination," delusional imagination ", today has become somewhat alarming reality." Addressing the audience, and answering the question whether nuclear energy is used for peaceful purposes or to destroy, G. said: "The answer must be given without hesitation, which undoubtedly scientists of the world will make every effort to win the first alternative."

In 1946, he became president of the Kaiser Wilhelm Society, renamed the Max Planck Society. He devoted much attention to the reorganization of the German scientific community. Speaking with public warnings about the dangers posed by a nuclear bomb, he united many physicists, fearing the consequences of the improvement of weapons. In 1959, on his 80th birthday, it was announced that the Institute of Nuclear Research in Berlin, will be renamed the Institute of the name Ghana - Meitner and Max Planck Institute for Chemistry in Mainz will be the Institute of Otto Hahn. A year later, G. resigned as president of the Max Planck Society.

In 1913, he married Edith Yunghans, the daughter of the chairman of Stettin city council. They had only one son. Shortly after his resignation, when he was 811 odes, his son and daughter died in France in a car accident, and he took care of his wife, who by that time became an invalid, and his grandson. G. died July 28, 1968 after a fall that led to the fracture of the cervical spine.

Among the many honors he received the medal Emil Fischer of the German Chemical Society (1922), Stanislao Cannizzaro Prize of the Royal Academy of Sciences in Rome (1938), the Max Planck Medal of the German Physical Society (1949), Gold Medal of Paracelsus, the Swiss Chemical Society (1953) and a medal Faraday British society of chemistry (1956). He was a member of academies around the world, had numerous honorary titles and was an officer of the Legion of Honor of France.