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Basic Chemical Kinetics 151

FIGURE 7.7 Lise Meitner (1878–1968) was an Austrian physicist who first described the splitting of a
uranium nucleus as ‘‘fission’’ and Otto Hahn (1879–1968) who was awarded the 1944 Nobel Prize in
chemistry for analyzing the elemental fragments of uranium fission. He missed the Nobel ceremony because
at the time he was a prisoner of war in a British camp. Meitner was later recognized for her key role in the
interpretation of Hahn’s data when the United States awarded her the Fermi Award jointly with Hahn and his
assistant Fritz Strassmann. Judging by her youthful appearance this was probably taken at the Kaiser Wilhelm
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Institute in Berlin in 1913. Details are given by David Bodanis in the historical novel ‘‘E ¼ mc .’’

charming young German named Otto Hahn when they met in college and at first she worked for him
and later he worked for her (Figure 7.7). She was much better at theory but he was a very good
chemist and they were working on trying to make a new element by aiming a beam of slow neutrons
at uranium hoping to make a new isotope but the uranium kept disappearing and quantities of
barium showed up in the beam target.
When Germany annexed Austria in 1938, Meitner who was formerly an Austrian citizen became
a German citizen. Then she could not remain at the Kaiser Wilhelm Institute because her parents
were Jewish (although she was baptized as a Christian in 1908). As a result, she went to the Niels
Bohr Institute in Stockholm, although she could not speak Swedish. She continued to correspond
with Hahn about their experiments and he apparently admitted he did not understand what was
happening to the uranium. This event and all the human drama is described by David Bodanis [9] in
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the historical novel ‘‘E ¼ mc .’’ While walking in the snow on a Christmas eve in 1938, in Sweden,
Lise Meitner and her nephew Robert Frisch added up the apparent atomic masses of the residual
elements found by Hahn and came to the astounding conclusion that about 1=4 of a proton mass was
missing and possibly converted into 200 MeV of energy in the form of flying particle debris. Hahn
had split the atom but Meitner interpreted the experiment. Hahn quickly published the results
ignoring her contribution and he was awarded the Nobel Prize in Physics in 1944. The oversight
of her slightly later paper, published in Nature (February 11, 1939) using the Bohr ‘‘Liquid Drop’’