Otto Hahn

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Image:Otto Hahn und Lise Meitner.jpg Otto Hahn (March 8, 1879 – July 28, 1968) was a German chemist and received the 1944 Nobel Prize in Chemistry. He is considered a pioneer in the field of radioactivity and radiochemistry, and in the words of Professor Glenn T. Seaborg, President of the US Atomic Energy Commission, "the father of nuclear chemistry".

[edit] Biography

Hahn was born in Frankfurt am Main and studied chemistry and mineralogy in Marburg and Munich. After receiving his Ph.D. in 1901 he worked initially at Marburg University then, from 1904, at London, where in the lab of Sir William Ramsay discovered radiothorium, and from 1905 at McGill University in Montreal under Ernest Rutherford, where he discovered thorium C, radium D and radioactinium. 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. From 1928 to 1945 he was director of the whole institute. 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." He was being held prisoner by the British at Farmhall near Cambridge as part of Operation Epsilon, who were seeking information from him about the failed German effort to develop an atomic bomb.

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 1959 president Charles de Gaulle named him an Officer of the French Legion of Honour, he was made a knight of the Order Pour-le-Mérite and received the Grand Cross of the Federal Republic of Germany. In 1961 Pope John XXIII awarded Otto Hahn the Gold medal of the Papal Academy.

In 1966 US-President Lyndon B. Johnson and the US Atomic Energy Commission in Washington D.C. 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). However, one of the world's few nuclear-powered merchant ships, Otto Hahn, was named in his honour. Many schools, high-schools, buildings, streets, squares and bridges in Europe bear his name, as well as two trains of the German Railway. In 1959 there were the opening ceremonies of the "Otto-Hahn-Institute" in Mainz and the "Hahn-Meitner-Institute (HMI)" in Berlin. There are craters on mars and moon, and the asteroid No. 19126 "Ottohahn", named in his honour, as well as the "Otto-Hahn-Prize" of the German Chemical Society, the "Otto-Hahn-Medal" of the Max-Planck-Society and the "Otto-Hahn-Peace-Medal in Gold" of the United Nations Association of Germany (DGVN) in Berlin.

[edit] Opinions

"Hahn is a capital fellow, and has done his work admirably. I am sure that you would enjoy having him to work with you." (Prof. Sir William Ramsay, London, to Prof. Ernest Rutherford, Montreal, 1905).

"He is a pleasant fellow, unassuming, completely trustworthy and highly talented - and I have come to like him very much. I can strongly recommend him as one of the best workers I know." (Prof. Sir William Ramsay, London, to Prof. Emil Fischer, Berlin, 1905).

"Hahn has a special nose for discovering new elements." (Prof. Ernest Rutherford, Montreal, 1906).

"He is doing the best work in Germany at present." (Prof. Sir Ernest Rutherford, Manchester, 1910).

"Dr. Hahn is not reliable of speech, when speaking of himself. He says he is not learned, not distinguished, not famous as a scientist. He sacrifices truth to modesty - and I sympathize with him in his temptation." (Dr. Ronald E. Knowles, Toronto, 1933).

"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." (Prof. Rudolf Ladenburg, Princeton, February 22th, 1939).

"It must certainly be a great joy for you and Strassmann that you have made the whole world of physics excited. That is really wonderful!" (Prof. Lise Meitner, Stockholm, to Otto Hahn, February 24th, 1939).

"Otto Hahn's humane and scientific personality is an indivisible whole. A very lively intellectual intuition, a very sound ability, an exceptional and critical ability for observation, an unshakeable dependability and doggedness next to great inner modesty and natural kindness mark the man as they do his work." (Prof. Lise Meitner, Stockholm, 1939).

"A man of the world. He has been the most helpful of the professors and his sense of humour and common sense has saved the day on many occasions. He is definitely friendly disposed to England and America." (Major Terence H. Rittner, Farmhall near Cambridge, summer 1945).

"Never has a Nobelprize-winner been in the outward sense so absent at a Nobel festival as Professor Hahn. And I suppose, too, that no Nobelprize-winner has ever, through the consequences of his discoveries, been so intensely present to our consciousness. Alfred Nobel hoped that in dynamite he had discovered such a powerful explosive that future wars would be impossible. The hope was not fulfilled; but dynamite is used today mostly for peaceful purposes. May we venture to hope the same of atomic energy? 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. We acclaim today this celebrated researcher's scientific achievements." (Prof. Axel Hugo Theorell at the Nobelprize ceremony, Stockholm, December 10th, 1945).

"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." (Prof. Samuel C. Lind, Minneapolis, 1951).

"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. This visit took place against resistance from the Foreign Office, for the Federal Republic of Germany had no diplomatic relations with Moscow." (Prof. Karl Winnacker, Bonn, 1955).

"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. The radiochemical methods he applied, which were partly developed by him, tested out hundreds of times in the course of thirty years, and found to be reliable, did not permit any doubt about the finding." (Prof. Fritz Strassmann, Mainz, 1956).

"Otto Hahn is a figure of world history. But he possesses none of the attributes of the traditional luminaries in history books. His slight, somewhat bowed figure, which with its high brow has the effect of his features having been carved, with his expression of searching honesty and critical inviolability, have something of a boundless nobility about them." (The Observer, London, June 9th, 1957).

"Hahn is an old wally who can not hold back his tears or sleep at night if he thinks of Hiroshima." (Franz Josef Strauss, German Minister of Defence, Bonn, 1957).

"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. The city at the same time stresses its bonds with a personality of exceptional talent and creative energy, whose scientific and administrative work serve progress and the well-being of the whole of humanity." (The attestation of honorary citizenship in the diploma of the city of Frankfurt am Main, 1959).

"Otto Hahn was also in Geneva. He was small and quiet, with a retiring manner. Little tufts of thin white hair framed his face, and there was often a bewildered expression in his blue eyes, as if he were still astonished at the great things that had come from his discovery of fission." (Dr. Laura Fermi, Chicago, 1961).

"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." (Prof. Lise Meitner, Cambridge, 1963).

"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. We admire him, who as a researcher in his work, just as much as a man in his thought and deed, was ever a model of uprightness and conscientiousness, and even more so by the questions and answers he raised and gave by virtue of his personal conduct." (Prof. Max Steenbeck, Berlin, 1964).

"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. He has made those contributions over a span of nearly two generations, beginning with a key role in the earliest days of radiochemistry in investigating and unraveling the complexities of the natural radioactivities and culminating with his tremendous discovery of the nuclear fission of uranium. I believe that it is fair to refer to Otto Hahn as the father of radiochemistry and of its more recent offspring, nuclear chemistry. For his special genius the world of science will be forever grateful." (Prof. Glenn T. Seaborg, President of the United States Atomic Energy Commission, Washington, 1966).

"In postwar Germany, Otto Hahn became the most revered elder statesman of what had once been Europe's proudest scientific establishment. He collected many awards, including a Nobelprize in Chemistry for his discovery of fission. But he always accepted such honours with characteristic humility. 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. Last week, at he age of 89, the father of fission died peacefully in his beloved Göttingen." (TIME Magazine, New York, August 9th, 1968).

"There are occurrences 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. A good, a simple man has entered his name in both the history of the natural sciences and the history of humanity. As long as intellect and character, scholarship and humanity maintain their value, Otto Hahn will be of relevance to the coming generations." (Prof. Walther Gerlach, Munich, 1968).

"Hahn remained modest and informal all his life. His disarming frankness, unfailing kindness, good common sense and impish humour will be remembered by his many friends all over the world." (Prof. Otto Robert Frisch, Cambridge, 1968).

"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." (Prof. Fritz Strassmann, Mainz, 1968).

"Otto Hahn's achievements are known universally and will hold a special place in the history of science. He is remembered too for his whole character, his generosity of spirit, his belief in the proper use of scientific discovery and for his humanity." (The Royal Society, London, 1970).

"He had an honesty and integrity which commanded the respect and trust of all." (Prof. Sir James Chadwick, Cambridge, 1970).

"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." (Prof. Robert Spence, London, 1970).

"I often thought, that he would have deserved a second Nobelprize - the Nobelprize for peace." (Prof. Elizabeth Rona, Miami, 1978).

"He was one of my models." (Prof. Linus Pauling, Pasadena, at he Nobel conference in Lindau, Bavaria, 1981).

"Otto Hahn is widely portrayed as a warm, considerate, charming person. The characterization is accurate. In fact, precisely because the personality of this decent human being suffered no great changes throughout his career, he offers us a touchstone to determined the extent of changes in scientists' perceptions of their obligations to society during the twentieth century. The important thing is not that scientists may disagree on where their responsibility to society lies, but that they are conscious that a responsibility exists, are vocal about it, and when they speak out they expect to affect policy. Otto Hahn, it would seem, was even more than just an example of this twentieth-century conceptual evolution; he was a leader in the process." (Prof. Lawrence Badash, Santa Barbara, California, 1983).

"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." (Prof. William R. Shea, Montreal, 1983).

"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. He could make things clear, he had to use his knowledge. And it is why Otto Hahn, with atomic weapons in mind, wrote shortly before his death of 'the necessity of world peace'." (Prof. Sir Karl R. Popper, Kenley near London, 1993).

"Thanks to his moral integrity Otto Hahn was trusted everywhere. He used it to point uncompromisingly to three important goals. For him the cessation of nuclear weapon tests, not transferring atomic weapons in order not to let the number of atomic powers become larger, and general disarmament were the essential challenges. Hahn occasionally emphasised that he was not a politician. Yet his speeches, appeals, warnings, and his appearance in public betrayed a purposeful political engagement. His distinctively humanitarian convictions directed him logically to this path. - 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. His engagement with science, humanity and peace is exemplary and to be remembered for following generations." (Dr. Klaus Hoffmann, Dresden, author of 'Otto Hahn - Achievement and Responsibility', New York etc. 2001).