Singlet-singlet intermolecular optical energy transfer from naphthalene to benzophenone in the vapor phase

By using the exothermic energy transfer as a function of pressure, the rate constant for diffusion was evaluated for benzophenone/naphthalene and naphthalene/benzophenone systems. In principle the optical energy absorbed by a complex molecule raises that molecule to one of its excited states, and afterwards this excitation energy decays through the different relaxation channels. Initially, electronically excited naphthalene "S-1" state emits photons in the fluorescence band of naphthalene and these emitted photons, as a stream of particles, are absorbed by the acceptor molecule benzophenone, then excited benzophenone fluoresces. In this investigation, sensitized fluorescence decay times in different conditions were measured for naphthalene-benzophenone system in the vapor phase, and found to be 12 +/- 1 ns. The ultraviolet-visible spectra of the system in the vapor phase at room temperature conditions were broad and structureless. (C) 2008 Elsevier B.V. All rights reserved.