DISTANCE DEPENDENCE OF ELECTRON-TRANSFER QUENCHING IN RIGID MEDIA - ADISCRETE SITE MODEL OF ELECTRON-TRANSFER AND ELECTRON-EXCHANGE

The quenching of the luminescence of five emitters which span lifetime s 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 da ta are analyzed according to a model of statistical distribution simil ar to the Perrin action sphere model, except that the distances betwee n emitters and quenchers are allowed to vary only in increments of the solvents' molecular diameter. It is concluded that in all studied cas es quenching takes place only if the two molecules are in van der Waal s contact. The distribution of charged species in highly polar liquids or glasses is considered specifically. It is suggested that even in s uch cases the simple statistical distribution is obtained.