In 1933 Strassmann resigned from the
Society of German Chemists when it became part of a
Nazi-controlled public corporation. He was
blacklisted by the Nazi regime. As a result, he could not work in the chemical industry nor could he receive his
habilitation, as required to be an independent researcher in Germany at the time. Strassman's wife Maria supported his refusal to join the Nazi Party.
Discovery of nuclear fission Hahn and Meitner made use of Strassmann's expertise in
analytical chemistry in their investigations of the products resulting from bombarding
uranium with
neutrons. Of these three scientists, only Strassmann remained focused on their joint experimental investigations. Meitner, being Jewish, was forced to leave Nazi Germany, and Hahn had extensive administrative duties. Pressure from historians, scientists and feminists caused the museum to alter the display in 1988 to acknowledge the contributions of
Lise Meitner,
Otto Frisch and Strassmann (right), whose images are now prominently displayed. In 1937 and 1938, scientists
Irène Joliot-Curie and Paul Savič reported results from their investigations on irradiating uranium with neutrons. They were unable to identify the substances that formed as a result of the uranium irradiation. Strassmann, with Hahn, identified the element
barium as a major end product in the neutron bombardment of uranium, through a
decay chain. The result was surprising because of the large difference in
atomic number of the two elements, uranium having atomic number 92 and barium having atomic number 56.
Robert Frisch confirmed Strassman and Hahn's report experimentally on 13 January 1939. Frisch and Meitner explained Strassman's and Hahn's findings as being from nuclear fission, which they named. In 1944, Hahn received the
Nobel Prize for Chemistry for the discovery of nuclear fission, although Fritz Strassmann had been acknowledged as an equal collaborator in the discovery.
World War II Working at the Kaiser-Wilhelm Institute from 1939 to 1946, Strassman contributed to research on the fission products of
thorium, uranium, and
neptunium. In this way, he contributed to the understanding of the radiochemistry of the
actinide elements. He developed methods for the dating of the age of minerals and other inorganic substances based on the half-life of radioactive elements and the enrichment of decay products. Strassmann and Ernst Walling developed the rubidium-strontium method of
radiometric dating in 1936 and 1937, and Strassmann continued this work in 1942 and 1943. His methods are known as emanation methods, and Strassmann's research in this area was fundamental to the field of
geochronology. On 15 February 1944 and again on 24 March 1944, the Institute suffered severe bombing damage. For this reason, the institute was temporarily relocated to Tailfingen (now
Albstadt) in the
Württemberg district, in a textile factory belonging to the Ludwig Haasis company. ==Post-war==