Deuterium isotope effects on photodecomposition of alkylbenzenes

摘要

Photodissociation of 11 alkylbenzenes (toluene, ethylbenzene, butylbenzene, and their deuterated compounds) have been studied by the ArF (193 nm) laser photolysis. Formation rate constants of benzyl radical were measured under collision free conditions. The major relaxation process of the photoexcited state is internal conversion to highly excited vibrational levels of the ground electronic state, i.e., hot alkylbenzene formation, followed by decomposition yielding benzyl radical. Deuterium isotope effects demonstrate that the bond fission occurs after intramolecular vibrational redistribution is complete.