fluorescence yield

For a given transition from an @E02257@ of a specified atom, the ratio of the number of excited atoms which emit a photon to the total number of excited atoms.
PAC, 1994, 66, 2513. (Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)) on page 2526 [Terms] [Paper]
See also:
Orange Book, 2nd ed., p. 174 [Terms] [Book]