Cover-Design-Dec-20
FEATURE ARTICLE 75 YEARS OF EXPLOSION OF THE ATOMIC BOMB
B.S. Jai Prakash and R. Venugopal
THE EXCITING STORY OF THE UNEARTHING OF THE MYSTERY OF NUCLEAR ENERGY THAT LED TO THE ATOMIC BOMBING OF JAPAN.
HE year 2020 marks the 75th committee publicized the news in the year of the explosion of the print media. British officers at the Farm Tnuclear bomb on Hiroshima Hall informed the news to Otto Hahn and Nagasaki on 6 August 1945, where he was under house arrest with resulting in innumerable death and nine other German scientists. Even sufferings of innocent people. Six though the scientists joined in greeting years earlier, two scientists who had Hahn, he was not elated by the news – in no connection whatsoever with this fact, he was depressed by the bombing bombing accidentally unearthed the in Japan that put the onus for the loss of mystery of nuclear energy in Berlin at so many lives on his discovery. the radiochemistry laboratory of Kaiser The story of Hahn and Meitner Wilhelm Institute. who had sown the seeds of the atomic Otto Hahn and Lisa Meitner bomb is full of stimulating events. opened the nuclear genie. This was Their efforts in the discovery, the in 1939 when the carnage of Hitler’s ethnic-gender discrimination and the Nazi Government was at its peak roller coaster ride in thirty years of and Meitner, being a Jew, had to association culminating in the Nobel Otto Hahn 1879-1968 escape to Sweden. The historic paper committee ignoring the contribution of of nuclear fission, authored by Otto Meitner for the discovery – makes for mineral from Ceylon (now Sri Lanka), Hahn and Fridge Strassmann, was exciting anecdotes. the element radium discovered by published in the 1940 January edition Marie Curie. Hahn not only succeeded of Naturwiseanschaften, unfortunately Otto Hahn in isolating radium, he also discovered with the omission of Lise Meitner’s Born in Frankfurt in 1870, Hahn got his a new radioactive isotope in the mineral name as coauthor. doctorate in organic chemistry from the which he named radiothorium. Three months after the explosion University of Marburg in the summer of Supremely happy with Hahn’s of the atomic bomb, to be precise 15 1904. In the winter of the same year, he work in a short time, Ramsay November 1945, Sweden’s Nobel received an invitation from the British recommended him for an appointment committee announced the 1944 Nobel Nobel laureate and the discoverer of as a radiation chemist at the laboratory Prize in Chemistry for Otto Hahn for noble gases William Ramsay with a of Nobel laureate Emil Fischer in his discovery of nuclear fission in heavy condition to learn English. He was Berlin. Wanting to get more experience elements. Unaware of his whereabouts assigned an arduous task of isolating in this field, Hahn joined another Nobel to send a formal invitation, the from 250 kg of a radioactive barium laureate Rutherford’s team at Montreal
34 | Science Reporter | December 2020 where he continued his research on radioactivity and contributed to the construction of the radioactive series of thorium. After his return to Berlin in 1907, Hahn introduced novel radiochemical techniques for isolation of radioisotopes at Kaiser Wilhelm Institute of Chemistry. Later, invited lectures on radiochemical techniques delivered by Hahn at different places were published with the title Applied Radiochemistry by Cornell University. This became an approved text for the course curriculum of Universities in USA, UK, Europe and the Soviet Union.
Lise Meitner Born in 1878 in Vienna to relatively wealthy cultured Jewish Austrian- Swedish parents, Lise Meitner, famously called German Mary Curie by Einstein, was especially interested Lise Meitner with Einstein and other scientists in pursuing mathematics and science. Pursuing physics, Meitner completed her doctoral research in 1905, becoming the first female from the University of Vienna and second in the world to earn a doctorate in physics; the first being Isabella Stone of the USA in 1897. Participation at Nobel laureate Max Planck’s course at the University of Vienna in 1907 encouraged Meitner to pursue her research on quantum physics under Planck at the Berlin University. Planck directed Meitner to meet Hahn at the Kaiser Wilhelm Institute of Chemistry since he was looking for an associate. Meitner
Lise Meitner in the lab with Otto Hahn
met Hahn who helped her to set up a repute – Einstein, Heisenberg, Niels laboratory – beginning a long academic Bohr, James Frank, von Baeyer and association of over three decades. Gustav Hertz. In 1912, the Hahn-Meitner team The First World War was just moved to the newly constructed Kaiser coming to an end. Wilhelm Institute where Meitner worked without salary, receiving her Hahn-Meitner-Strausman & Fermi first remuneration in 1915 when she Hahn and Meitner discovered hitherto was appointed as Professor at the Berlin unknown phenomena in radioactivity University. Planck developed high and a number of new radioisotopes. admiration for Meitner and invited her And the Kaiser Wilhelm Institute for at his parties for distinguished foreign Chemistry got recognition as a reputed scientists and delegates where Meitner centre of radiochemistry. During 1920- established contact with scientists of 1930 their names were recommended
December 2020 | Science Reporter | 35 several times for the Nobel honour in that contravened the earlier result. at the border security if demanded. Chemistry and Physics. Hahn shared this with Meitner. Little Coster, a frequent traveller between Fridge Strassman, a bright young did they know that solving this puzzle Germany and the Netherlands, escorted chemist, joined the team in 1932. The would make them epoch makers in the her to the border. Assuming Meitner to team of Hahn-Meitner-Strassman, history of science. be his wife, the border security raised popularly known as the Berlin team, At this prime moment in her no questions. continued the work of revealing the career, Meitner was blissfully unaware After three months of her escape obscurities of radionuclides. of the twist of fate in her life to follow. from Berlin, in November 1938, Nazis In 1932, the Nobel Prize-winning looted houses and business offices of discovery of the neutron by James Meitner Goes into Exile Jewish descent in Berlin and killed Chadwick was also creating waves in In 1933, the Nazi Government revoked Jews indiscriminately. Meitner had nuclear physics. Between 1932 and the assignment of Meitner as Professor just escaped from Germany at the right 1936 the mercurial Italian physicist at the Berlin University. For the next time. Enrico Fermi bombarded several five years, Hahn accommodated her in elements with neutron as projectile the Kaiser Wilhelm Institute Radiation Hahn’s Research Continues and published about the formation of laboratory. In 1938, Germany captured Hahn and Strassman continued their artificial radioisotopes. One of Fermi’s Austria, her homeland, and Meitner lost work on resolving the puzzle of radium papers astonished the scientific world the validity of her passport. News came in the complex mixture of uranium on the report regarding the unexpected in of genocide committed by the army bombarded with slow neutrons. formation of new elements beyond on Jews in Austria. Not able to protect Adopting scrupulous analytical uranium (transuranium elements) when a Jew any more at his Institute, Hahn radiochemical techniques, used several bombarded by slow neutrons. Fermi and other friends secretly planned for times in their previous work, they found reported two elements beyond uranium her escape from Germany. Her Swedish that the radium under investigation and even named them. cousin Otto Frisch requested his friend, was not radium but indeed a barium The Berlin team geared up to Dutch Physicist Dirk Coster to facilitate radioisotope. Hahn shared the findings disentangle the conundrum of the Meitner’s escape from Berlin to cross with Meitner. Uranium breaking formation of transuranium elements over at the Dutch border. into barium, a phenomenon beyond a during the slow neutron bombardment The date and time of Meitner’s chemist’s comprehension, required an of uranium. Induced radioactivity with escape were top-secret. On the fateful explanation from the physicist Meitner slow neutrons resulting in multiple day of July 1938, not to raise any to back up. radioisotopic activity was known doubt, Meitner worked as usual in the In December 1938, Hahn and by Fermi’s experiments. The Berlin laboratory and spent her evening at Strassman reported their findings to group soon realised that unscrambling Hahn’s home. Hahn gave her a diamond Naturwiseanschaften omitting the this puzzle would be an arduous task ring inherited from his mother to bribe name of Meitner as coauthor. The when they observed a plethora of paper merely mentioned the induced radioactive isotopes in the possibility of the presence mixture after bombardment. In those of elements of intermediate- times, separation and identification mass numbers in the neutron of hundreds of radioisotopes with bombarded uranium. Perhaps, the available instruments based on for want of a clear explanation, their half-lives and radiation tracks Hahn hesitated to reveal the required extraordinary radiochemical presence of barium though skills. Hahn had vast experience in there was a clear proof of its radiochemical separations and thorough presence. knowledge in co-precipitation carrier Hahn wrote to Meitner characteristics of radium, thorium and on 19 December 1938: ‘...the other elements near uranium. To say isotope what we have noticed that Hahn was the only chemist who is not that of radium but we could take up this challenge at that point have to decide that it is indeed of time may not be an unjust statement. barium. The theory we know Meitner’s association of thirty prohibits such a bursting of years with Hahn and her extensive uranium to barium. …Perhaps knowledge in radiation physics was a you have an explanation for big resource to the team. Resuming this.’ the work on the separation of different On 21 December, Meitner isotopes in the mixture, Hahn and replied: ‘A reaction with slow Strassman focused on radium isotopes. neutrons that supposedly leads Several repeats of the experiments to barium! ...At the moment puzzled them with an unexpected result the assumption of such a
36 | Science Reporter | December 2020 thoroughgoing breakup seems very learning about fission of nucleus, Bohr, Nobel prize to Hahn? Is this because difficult to me, but in nuclear physics, the proponent of liquid drop model, of her Jewish descent and Hahn’s we have experienced so many surprises exclaimed, ‘How foolish we are, why self-protection? Why does the Sweden that one cannot unconditionally say it is did it not occur to us before!’ committee ignore Meitner’s name impossible.’ Bohr placed the news of splitting for the 1944 Nobel honour? Was her This reply makes history in nuclear the uranium atom before his university significant contribution and multiple science. fellow scientists at Princeton and nominations for the award overlooked? Encouraged by the backup from Columbia. The news of the possibility Another question: Had Hahn missed Meitner, Hahn adds another passage to of enormous energy release spread like seeing barium in the mixture, would his paper. wildfire creating panic. it have delayed the end of the Second ‘...In addition to the transuranium Meitner and Frisch’s paper on World War? Perhaps. elements reported by Fermi, we have nuclear fission appeared on 11 February In 1933, Max Planck and Robert found a clear experimental proof for 1939. Release of a huge amount of Bosch cautioned Hitler about the the presence of barium along with energy, of a different kind by splitting exodus of eminent basic science possibility of elements 43 through nucleus, becomes a distinct possibility. professors of Jewish descent. Hitler 46 in the soft neutron bombarded Hahn and Meitner had opened the remarked with disdain, “Germany is in uranium. Perhaps uranium bursts gate to the atomic age – from chemical no need of physicists and chemists for (Ger: urasplatung) into barium.’ fuel to atomic fuel. The nuclear bomb another hundred years.” Was Hitler’s became the first use of atomic fuel. faith in his military stronger than his Christmas holidays had just Nobel laureate chemist Glenn faith in German science? Did this lead begun. Hahn speaks over the phone to Seaborg refers to Hahn as the father to the failure of Germany to produce the chief editor of Naturwiseanschaften of nuclear and radiochemistry. the bomb even though the discovery of to include the passage in his paper. It was Hahn’s book on Applied fission was made in Berlin? Radiochemistry that helped him to The milestone paper on urasplatung Hahn and Meitner continue to appeared on 6 January 1939. separate plutonium so quickly to make the plutonium bomb. maintain harmonious understanding In 1954, Meitner in a radio even after Hahn received the Nobel Meitner’s Explanation for interview says, “...Hahn and honour. Meitner participated in the Urasplatung Strassmann were able to do this award ceremony on 16 December Meitner’s cousin Otto Frisch, who by exceptionally good chemistry, 1946. In his Nobel speech, Hahn was a researcher with Bohr on liquid fantastically good chemistry, which recognized her contribution and praised drop model of the nucleus, visited was way ahead of what anyone else was her involvement. He gave due credit to capable of at that time. The Americans Meitner and Frisch for using the term Meitner in the Christmas holidays of learned to do it later. But at that time, 1938. While taking a walk, Meitner Hahn and Strassmann were really the nuclear fission and admitted that they shared the findings of Hahn on neutron only ones who could do it. And that was were the first to realise the possibility bombardment of uranium. She tells because they were such good chemists. of enormous energy release. Frisch, ‘If barium is present as Hahn Somehow they really succeeded in Hahn shared the prize money says, then uranium is split, and it using chemistry to demonstrate and with Meitner who gracefully accepted. should accompany enormous energy. prove a physical process...” She contributed it to Albert Einstein’s Let us calculate the energy released.’ In the same interview, Strassmann Emergency Committee of Atomic responded: “Professor Meitner stated She takes her notebook, scribbles Scientists promoting peaceful uses of that the success could be attributed atomic energy. and exclaims ‘it is about 200 MeV’; to chemistry. I have to make a slight a figure several orders of magnitude correction. Chemistry merely isolated of TNT energy. Her calculation just the individual substances; it did required the mass defect and Einstein’s not precisely identify them. It took relation E=mc2. Both parameters were Professor Hahn’s method to do this. Dr B.S. Jai Prakash was with the Department known but getting this energy out was a This is where his achievement lies.” of Studies in Chemistry at Central College, million-dollar question. Delay in recognising the contribution of Meitner was Bangalore University for more than 10 years Using Bohr’s liquid drop compensated in an exceptional manner. before he joined the Bangalore Institute of model Meitner and Frisch wrote a In 1982, the International Union of Technology as Professor of Chemistry. paper explaining the mechanism of Pure and Applied Chemistry (IUPAC) Presently he is the Director of the Institute urasplatung naming it nuclear fission. named element 109 as Meitnerium, of Environment and Hazardous Materials A simple illustration of absorption of immortalizing Lise Meitner. Management. neutron by uranium splitting into two Email: [email protected] halves releasing large amount of energy Put through the Wringer Prof. R. Venugopal retired as Professor is the crux of the paper. The journal Between 1935 and 1938, the Berlin in the year 2000 from the Visveswarapura Nature received it on 16 January 1939. team published jointly seven papers College of Science. He is the winner of the On the same day, Meitner and on uranium bombardment. Why is Best Science Writer Award for the year 2017 Frisch met with Bohr who was rushing Meitner’s name omitted as a coauthor from Karnataka Science and Technology to visit Einstein at Princeton. After in the eighth paper which fetches the Academy (KSTA).
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