Physical chemist, born in Frankfurt, WC Germany. He studied at the University of Marburg, and lectured in Berlin from 1907, becoming director of the Kaiser Wilhelm Institute there in 1927. With Meitner he discovered the radioactive element protactinium (1917), and in 1938 bombarded uranium with neutrons to find the first chemical evidence of nuclear fission products. He was awarded the Nobel Prize for Chemistry in 1944.
Otto Hahn (8 March 1879 – 28 July 1968) was a German chemist and received the 1944 Nobel Prize in Chemistry.
Biography
Hahn was born in Frankfurt am Main and studied chemistry and mineralogy in Marburg and Munich. Back in Berlin, Hahn discovered mesothorium I (radium 228), mesothorium II and - independently from Boltwood - the mother substance of radium, ionium. In the winter 1908/09 Hahn discovered the radioactive recoil.
Hahn became professor in 1910 and head of the department of radioactivity at the newly founded Kaiser-Wilhelm-Institute for Chemistry in Berlin in 1912. In 1924 Hahn was made an member of the Prussian Academy of Sciences.
In 1918, he, together with Lise Meitner, discovered the first long-lived isotope of protactinium. In 1921 Otto Hahn discovered nuclear isomerism (uranium Z) and in 1933 Hahn was a visiting professor (for nuclear chemistry) at Cornell University, Ithaca, New York (USA). When Lise Meitner, with Hahn's help, fled Nazi Germany in July 1938, he continued the work with his assistant Fritz Strassmann on elucidating the outcome of the bombardment of uranium with thermal neutrons. Hahn and Strassmann, on December 17th, 1938, discovered the existence of barium (and soon after krypton) as fission products and Hahn concluded, that the uranium nucleus did "burst" into lighter elements. He communicated his results to Meitner who, in collaboration with her nephew Otto Robert Frisch, correctly interpreted them as evidence of nuclear fission, a phrase coined by Frisch. Thus Otto Hahn is credited as having been the first person to split the nucleus of the atom.
Once the idea of fission had been accepted, Hahn continued his experiments and demonstrated the huge amounts of energy that neutron-induced fission could produce, either for energy production or warfare.
After World War II Hahn was among those German scientists put under surveillance by the Allied Alsos program who suspected him of working on the German nuclear energy project to develop an atomic bomb (his only connection was the discovery of fission, he did not work on the program). In 1945 Hahn was awarded the 1944 Nobel Prize in Chemistry ("for the discovery of the fission of heavy nuclei"), but at the awards ceremony the chairman of the Nobel Committee for Chemistry announced, "Professor Hahn has informed us that he is regrettably unable to attend this ceremony."
In the post-war era Hahn founded the Max-Planck-Society for the Advancement of the Sciences, of which he was President from 1948 to 1960, and became an outspoken advocate against the use of nuclear weapons, drafting several declarations, so, for instance, in 1955 the Mainau Declaration and in 1957 the "Declaration of the 18 Nuclear Scientists" against the establishing of the German Bundeswehr with atomic weapons.
Hahn was awarded many honours from all over the world, was elected member or honorary member in 45 academies and scientific societies and received 37 highly regarded national and international orders and medals. In 1961 Pope John XXIII awarded Otto Hahn the Gold medal of the Papal Academy.
In 1966 US-President Lyndon B. awarded Otto Hahn the Enrico- Fermi-Prize (together with his colleagues Lise Meitner and Fritz Strassmann).
Otto Hahn, honorary citizen of the cities of Frankfurt am Main and Göttingen and the state and city of Berlin, died at July, 28th, 1968.
Proposals were made at different times that each of elements 105 and 108 should be named Hahnium in Hahn's honour, but neither proposal found approval (see Element naming controversy).
Opinions
"Hahn is a capital fellow, and has done his work admirably.
"He is a pleasant fellow, unassuming, completely trustworthy and highly talented - and I have come to like him very much.
"Hahn has a special nose for discovering new elements."
"He is doing the best work in Germany at present."
"Dr. Hahn is not reliable of speech, when speaking of himself.
"Your discovery has caused a huge sensation in the whole scientific world, and every laboratory which has the necessary means is now working on the consequences of your discovery."
"It must certainly be a great joy for you and Strassmann that you have made the whole world of physics excited. Lise Meitner, Stockholm, to Otto Hahn, February 24th, 1939).
"Otto Hahn's humane and scientific personality is an indivisible whole.
"A man of the world.
"Never has a Nobelprize-winner been in the outward sense so absent at a Nobel festival as Professor Hahn. Hahn's discovery of the cleavage of atoms is the crowning feat, so far, in a series of discoveries for which Nobelprizes have been awarded.
"No living man has so successfully spanned the world of discovery from radiothorium to fission, one of the greatest - if not the greatest - discovery of all times."
"With his humour and his sound humanity Otto Hahn quickly gained ground at the Geneva Conference to which we other members of the German delegation became very indebted. We even went to the official Soviet reception, at which we were also able to bask in Hahn's fame.
"The significance accorded to the outcome from the scientific point of view becomes clear when one reads in the first publication of nuclear fission that Professor Hahn, who had over thirty years of practical and theoretical experience in the sphere of radioactivity and whose judgement unquestionably commanded the greatest weight among fellow scientists both in Germany and the whole world, announced the new discovery only hesitatingly.
"Otto Hahn is a figure of world history.
"Hahn is an old wally who can not hold back his tears or sleep at night if he thinks of Hiroshima."
"His father city Frankfurt am Main thus honours a scholar of worldwide fame, who, as a result of his trail-blazing discoveries in the sphere of atomic research, radioactivity and radiochemistry, enjoys a surpassing reputation in the world.
"Otto Hahn was also in Geneva.
"I must emphasise, that this proof of fission with such a low presence of the identifying preparation was in actuality a masterpiece of radiochemistry, in which at that time hardly anybody else other than Otto Hahn and Strassmann would have been able to succeed."
"Can one, may one, hold the researcher responsible for the consequences of his work? Everyone who knew Otto Hahn knew with what unsparing clarity he had put this question to himself.
"It has been given to very few men to make contributions to science and to humanity of the magnitude of those made by Otto Hahn. I believe that it is fair to refer to Otto Hahn as the father of radiochemistry and of its more recent offspring, nuclear chemistry.
"In postwar Germany, Otto Hahn became the most revered elder statesman of what had once been Europe's proudest scientific establishment. Visiting an atomic reactor or nuclear power station, he would shrug modestly: 'It has all been the work of others.' In a soon-to-be-published 300-page memoir, he brushed off his historic work in fewer than five pages.
"There are occurences far removed from social and political events, let alone any sensation, and without relation to the course of history - and yet their taking place leads the world, deeply moved, to hold its breath for a moment, and people, far and wide, to halt for a moment of reflection amid the rush of the everyday: Otto Hahn, almost 90 years old, has left the world. As long as intellect and character, scholarship and humanity maintain their value, Otto Hahn will be of relevance to the coming generations."
"Hahn remained modest and informal all his life.
"The number of those who had been able to be near Otto Hahn is small. His behaviour was completely natural to him, but for the next generations he will serve as a model, regardless of whether one admires in the attitude of Otto Hahn his humane and scientific sense of responsibility or his personal courage."
"Otto Hahn's achievements are known universally and will hold a special place in the history of science.
"He had an honesty and integrity which commanded the respect and trust of all."
"It was remarkable, how, after the war, this rather unassuming scientist who had spent a lifetime in the laboratory, became an effective administrator and an important public figure in Germany. Hahn, famous as the discoverer of nuclear fission, was respected and trusted for his human qualities, simplicity of manner, transparent honesty, common sense and loyalty."
"I often thought, that he would have deserved a second Nobelprize - the Nobelprize for peace."
"He was one of my models."
"Otto Hahn is widely portrayed as a warm, considerate, charming person. Otto Hahn, it would seem, was even more than just an example of this twentieth-century conceptual evolution;
"The discovery by Otto Hahn that the uranium nucleus could be split marks, on the one hand, the culmination of one of the most fascinating periods in the history of physics and, on the other, heralds the advent of a new age in Man's understanding and mastery of nature."
"Ever since my early youth, I have admired Otto Hahn as a scientist and a human being. The reason for Hahn's peace work was simply that, knowing more than other citizens about atomic weapons, he felt it his duty to speak about this issue that was so crucial for mankind. And it is why Otto Hahn, with atomic weapons in mind, wrote shortly before his death of 'the necessity of world peace'."
"Thanks to his moral integrity Otto Hahn was trusted everywhere. Hahn occasionaly emphasised that he was not a politician. - As we must conclude, Otto Hahn is not to be held personally responsible for the consequences of his discovery, but he suffered from them and because of the constantly smouldering conflicts of conscience became a tireless watchman for the world of a life worth living, at peace, without anxiety caused by the atom. (Dr. Klaus Hoffmann, Dresden, author of 'Otto Hahn - Achievement and Responsibility', New York etc.
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