Franck, James (1882-1964), a German-born American scientist, collaborated with Gustav Hertz in 1914 to prove the Niels Bohr theory of atomic structure. Franck and Hertz shared the 1925 Nobel Prize in physics for research proving that electrons occupy certain energy levels in atoms.

This research confirmed Bohr's theory. Franck also won recognition for his research in photochemistry and photosynthesis. He was awarded the Max Planck Medal in 1953. Franck was also an outspoken critic of the use of atomic weapons for purposes of aggression.

Franck was born in Hamburg, Germany, and studied at Heidelberg and the University of Berlin. He received his doctorate in 1906. Franck served in the German army during World War I (1914-1918), and received the Iron Cross.

Franck emigrated to the United States in 1935 to escape from Adolf Hitler's racist regime. From 1935 to 1938 he was a professor at Johns Hopkins University in Baltimore. He then moved to the University of Chicago, where he taught physical chemistry and conducted research. In 1949, he became professor emeritus and stayed active in research. He became a U.S. citizen in 1941.

During World War II (1939-1945), Franck worked on the Manhattan Project, the United States program to produce the first atomic bomb. Franck's motivation was to help the United States develop this weapon before Germany could do so. However, he felt strongly that the atom bomb should be used for deterrence, not destruction. He chaired a committee that issued a document that became known as the Franck Report. It recommended that the atomic bomb be demonstrated in a remote area rather than dropped on a Japanese city, advocated international control of nuclear weapons, and cautioned against a possible arms race.

He died in 1964 while visiting Göttingen, Germany, which had previously named him an honorary citizen.