On the contribution of excimers to the transfer of excitation energy in liquid alkylbenzenes

Abstract

The influence of excimer formation on the process of energy transfer in toluene and mesitylene is illustrated. At room temperature both liquids transfer energy very efficiently to a fluorescent acceptor, diphenyloxazole. At low temperatures, however toluene forms excimers which are stable throughout the lifetime of the excited state. Energy transfer can therefore only take place by long range interaction between the excimer and the acceptor. For mesitylene the situation is quite different. Even at low temperatures the excimer disintegrates and reforms so that during the disintegration period energy transfer from the excited monomer by singlet exciton migration is possible.