The heavy atom effect on the phosphorescence of aromatic hydrocarbons. I

Abstract

The decay of phosphorescence in a rigid solution perturbed by the heavy atom effect is treated theoretically. The enhancement of the spin-orbit interaction is discussed and it is found that when the phosphorescent molecules and the heavy atom species are far apart, i.e., when their concentrations are dilute, the heavy atom quenching rate follows the inverse fourth-power rate law. Theoretical expressions for the decay function, relative yield, mean duration etc., based on this rate law for the heavy atom effect are derived and illustrated.