ˈfraŋkˈkändən-, -räŋ- noun
Usage: usually capitalized F&C
Etymology: after James Franck died 1964 American physicist born in Germany and Edward U. Condon b 1902 American physicist
: a principle in spectroscopy: the intensities of molecular spectral bands due to electronic transitions are consistent with the assumption that the relatively large mass of the atomic nuclei in the molecule prevents appreciable change in their configuration during such transitions