Intermolecular Electronic Energy Transfer in the Gas Phase

Abstract

The kinetics of triplet-triplet energy transfer in the gas phase has been studied for various donor-acceptor pairs of aromatic hydrocarbons and ketones. For all the donor-acceptor pairs investigated the triplet-triplet energy transfer efficiencies are much lower than unity. The triplet triplet energy transfer was used to gain insight into the paths of intramolecular excitation energy degradation in benzophenone and anthraquinone vapours and to obtain sensitized anti-Stokes annihilation delayed fluorescence of vapours of anthracene and its derivatives. The intermolecular triplet-triplet transfer (T-T transfer) of excitation energy and sensitized phosphorescence were first discovered in 1952 by Terenin and Yermolayev in organic solutions¹. Later these phenomena became known for liquid solutions², crystals³, and also for vapours^4-10. And though the nature of interactions underlying the T-T energy transfer phenomena in different aggregate states is the same, a number of specific features is observed in the vapour phase. The study of these processes makes it possible to obtain additional information on interacting molecules.