Distance Dependence of Electron-Transfer Quenching in Rigid Media: A Discrete Site Model of Electron Transfer and Electron Exchange

Abstract

The quenching of the luminescence of five emitters which span lifetimes of 1 ns to 10 s has been investigated in rigid media. The mechanism is in every case either electron transfer or electron exchange. The data are analyzed according to a model of statistical distribution similar to the Perrin action sphere model, except that the distances between emitters and quenchers are allowed to vary only in increments of the solvents' molecular diameter. It is concluded that in all studied cases quenching takes place only if the two molecules are in van der Waals contact. The distribution of charged species in highly polar liquids or glasses is considered specifically. It is suggested that even in such cases the simple statistical distribution is obtained.