Otto Hahn and Lise Meitner. Meitner's nephew, Otto Robert Frisch, said that Meitner's university teacher, Ludwig Boltzmann, “gave her the. Key words: Otto Hahn; Lise Meitner; Fritz Haber; Max von Laue; Max Planck, Ernst in constructing that image, and the issues of suppression and denial that .. office, to discuss the “very disturbing things in connection with the treatment of J. Also, albeit unintentionally, Lise Meitner probably contributed as Report an accessibility issue . Through Planck, Meitner met Otto Hahn, a German chemist also With their respective expertise in physics and chemistry, the two soon initiated a research relationship that continued for three decades.
As Chadwick and others were attempting to prove the existence of the neutronMeitner sent polonium to Chadwick for his experiments. Chadwick eventually required and received more polonium for his experiments from a hospital in Baltimorebut he would remain grateful to Meitner. After the discovery of the neutron in the early s, the scientific community speculated that it might be possible to create elements heavier than uranium atomic number 92 in the laboratory.
At the time, all concerned believed that this was abstract research for the probable honour of a Nobel prize. None suspected that this research would culminate in nuclear weapons.
When Adolf Hitler came to power inMeitner was still acting as head of the physics department of the Kaiser Wilhelm Institute for Chemistry.
Most of them emigrated from Germany. Her response was to say nothing and bury herself in her work.
- Lise Meitner’s fantastic explanation: nuclear fission
After the Anschluss in Marchher situation became difficult. She was forced to travel under cover to the Dutch border, where Coster persuaded German immigration officers that she had permission to travel to the Netherlands. She reached safety, though without her possessions. Before she left, Otto Hahn had given her a diamond ring he had inherited from his mother: It was not required, and Meitner's nephew's wife later wore it.
Here she established a working relationship with Niels Bohrwho travelled regularly between Copenhagen and Stockholm. She continued to correspond with Hahn and other German scientists.
Later they continued to exchange a series of letters. In December Hahn and his assistant Fritz Strassmann performed the difficult experiments which isolated the evidence for nuclear fission at their laboratory in Berlin-Dahlem.
The surviving correspondence shows that Hahn recognized that 'fission' was the only explanation for the presence of barium at first he named the process a 'bursting' of the uraniumbut, baffled by this remarkable conclusion, he wrote to Meitner.
The possibility that uranium nuclei might break up under neutron bombardment had been suggested years before, notably by Ida Noddack in However, by employing the existing "liquid-drop" model of the nucleus,  Meitner and Frisch, exclusively informed by Hahn in advance, were therefore the first to articulate a theory of how the nucleus of an atom could be split into smaller parts: She and Frisch had discovered the reason that no stable elements beyond uranium in atomic number existed naturally; the electrical repulsion of so many protons overcame the strong nuclear force.
Lise Meitner | jingle-bells.info
Nuclear fission experimental setup, reconstructed at the Deutsches MuseumMunich A letter from Bohr had sparked the above inspiration in December But Meitner and Frisch later confirmed that chemistry had been solely responsible for the discovery, although Hahn, as a chemist, was reluctant to explain the fission process in correct physical terms.
In a later appreciation Lise Meitner wrote: It seems to me that what makes the science behind this discovery so remarkable is that it was achieved by purely chemical means. The Americans learned to do it later.
But at that time, Hahn and Strassmann were really the only ones who could do it. And that was because they were such good chemists. Somehow they really succeeded in using chemistry to demonstrate and prove a physical process. Fritz Strassmann responded in the same interview with this clarification: The main purpose of that measurement was to test the Klein-Nishina formula for the Compton effect, and she found good agreement for light elements, up to magnesium.
She discovered, however, that attenuation increased with atomic number ; she suspected an effect of nuclear structure, perhaps a resonance, and therefore searched for the scattering of gamma rays with unchanged wavelength. In it was discovered that the excess attenuation was due to the formation of electron-positron pairs, rather than to scattering. Meitner and her colleagues published a number of short papers in the light of these rapid developments.
In Meitner resumed work with Hahn to follow up results obtained by Fermi, who had bombarded uranium with neutrons and had found several radioactive products which he thought must be due to a transuranic element since neutron bombardment had invariably led to the formation of a heavier, usually beta-radioactive, isotope of the bombarded element except for the lightest elements, where a nucleus of lower atomic number might result from the ejection of a charged particle such as a proton or a helium nucleus.
In his investigation of this phenomenon, Hahn discovered several decay products for uranium, some of which might be presumed to be transuranic, with atomic numbers greater than He and Meitner set out to isolate such elements by precipitating an irradiated and acidified uranium salt solution with hydrogen sulfide in order to eliminate all elements between polonium 84 and uranium 92 ; they assumed that the remaining precipitate must contain only transuranic elements.
To be sure, Ida Noddack had suggested that the formation of transuranic elements could not be regarded as proven until it could be established that such elements were not, in fact, identical with any elements between hydrogen and uranium, but her paper was little read and uninfluential.
Meitner and Hahn were thus considerably surprised when Irene Curie and Savitch reported irradiating uranium to find a product with penetrating beta rays and a half-life of three-and-one-half hours.
Curie further noted that this substance behaved chemically somewhat like thorium. Hahn and Meitner, using sulfide precipitation, would have misled that. By implication, then, a uranium nucleus upon being hit by a neutron might emit an alpha particle —a helium nucleus—which seemed unlikely.
Later Curie changed her view and pointed to the similarity of her three-and-one-half-hour substance with lanthanum, foreshadowing, but not formulating, the concept of nuclear fission.Lise Meitner
Meitner set one of her students, Gottfried von Droste, to look for such alpha particles, but he failed to find them. By studying substances not precipitated as sulfide, Hahn and Strassmann found yet more products, with actinium-like properties and, startlingly, three others with the properties of radium, four places below uranium on the atomic scale.
These results puzzled Meitner, who was unable to reconcile them with nuclear theory. It was at this point, however, that she was forced to interrupt her researchse and leave Germany, where the Nazi racial laws had made it increasingly difficult for her to work.
Lise Meitner’s fantastic explanation: nuclear fission | ANS Nuclear Cafe
She had never concealed her Jewish origin; her Austrian passport was invalid, and her dismissal from the institute certain. No one except Hahn knew that she was leaving Germany for good. Meitner remained in Holland for only a short time, then went to Denmark, where she was the guest of Niels Bohr and his wife.
Although Copenhagen offered her good facilities for research, and although there were a number of younger nuclear physicists working there including her nephew, O. FrischMeitner soon chose to accept an invitation from Manne Siegbahn to work in the new Nobel Institute in Stockholm, where a cyclotron was being constructed. Meitner was sixty years old when she went to Sweden; she nonetheless acquired a good command of the language, built up a small research group, and eventually published a number of short papers, most of them on the properties of new radioactive species formed with the cyclotron.
Meitner made her most famous contribution to science shortly after she arrived in Stockholm, however. Her request led Hahn and Strassmann to undertake a series of tests designed to demonstrate that these products were chemically identical to radium, as their earlier investigations had suggested. Hahn wrote to inform her that in these tests, he and Strassmann had found that, like radium, these substances could be precipitated with barium but, surprisingly, were then inseparable from it.
They therefore reluctantly concluded that the decay products were isotopes of barium, rather than radium. Hahn was a brilliant, methodical, and precise chemist, while Meitner was a brilliant theorist attempting to puzzle out his laboratory results. It was a perfect scientific partnership.
A fantastic explanation At their secret meeting inMeitner urged Hahn and his laboratory partner Strassman to perform additional tests on neutron-bombarded uranium.
Hahn recognized that uranium atoms completely breaking apart into much smaller atoms would be an explanation, but how could that happen? Hahn wrote to Meitner: They scribbled formulas on a scrap of paper in the woods: Hahn, however, continued to maintain that he was the sole discoverer of fission, through accepting the Nobel Prize in and for the rest of his life. I am part of his suppressed past. Element is named meitnerium in her honor. This entry was posted in EducationNuclear pioneersphysics by ansnuclearcafe.