born July 2, 1906, Strassburg, Ger.
German-born U.S. theoretical physicist.
He fled Germany in 1933 and taught at Cornell University (193775). He showed how the electric field surrounding an atom in a crystal affects the atom's energy states, work that helped shape quantum mechanics and increased understanding of the forces governing the structures of atomic nuclei. He was the first to propose the carbon cycle as a source of energy production in stars (1939). He headed the theoretical physics division of the Manhattan Project , but he worked in the postwar era to publicize the threat of nuclear warfare. He was awarded the Max Planck Medal (1955) and the Enrico Fermi Award (1961), and he received the 1967 Nobel Prize for Physics.