1882-1964. US physicist influential in atom
technology. He was awarded a Nobel prize 1925
for his experiments of 1914 on the energy
transferred by colliding electrons to mercury
atoms, showing that the transfer was governed
by the rules of quantum theory. Born and
educated in Germany, he emigrated to the US
after publicly protesting against Hitler's
racial policies. Franck participated in the
wartime atomic-bomb project at Los Alamos but
organized the `Franck petition' 1945, which
argued that the bomb should not be used
against Japanese cities. After World War II
he turned his research to photosynthesis.