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OTTO HAHN

Otto Hahn was the chemist whose discovery of nuclear fission ultimately led to the ending of WW II. The story of Hahn's discovery began in 1938 with a report by Irène Joliot-Curie that bombarding uranium with neutrons had resulted in the production of a radionuclide of thorium, which they later speculated was a transuranium element similar to lanthanum. The astounded Hahn told Irène's husband, Frédéric, that such a thing was nonsense and that he would perform an experiment to prove as much. In the process of duplicating her work, Hahn and co-worker Fritz Strassmann discovered that, among other things, three isotopes of barium had been produced. This was incredible because the mass of barium is about half that of uranium. No known reaction could explain such a huge change. When they published their results (Jan. 6, 1939) Hahn and Strassmann noted that such a thing was "in opposition to all the phenomena observed up to the present in nuclear physics." Hahn, conscious of the fact that as a chemist he was treading in the domain of physics, did not offer an explanation. Instead, he left it up to Lise Meitner, his longtime collaborator, to whom he had sent a letter (December 19, 1938) describing his findings and asking "Perhaps you can suggest some fantastic explanation," which she explained as nuclear fission. Nevertheless, despite the contributions of Strassmann and Meitner, it was Hahn who was awarded the 1944 Nobel Prize in chemistry for the discovery. Unfortunately, Hahn was not at the awards ceremony to receive his prize. At the time he learned of the award, he was being held by the British who were seeking information from him about the failed German effort to develop an atomic bomb. As the Chairman of the Nobel Committee for Chemistry reported "Professor Hahn . . . has informed us that he is regrettably unable to attend this ceremony."

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