Triplet-triplet energy transfer from naphthalene to biacetyl in the vapor phase.

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 emits photons in the phosphorescence band of naphthalene and these emitted photons are absorbed by the acceptor molecule biacetyl, then excited biacetyl phosphoresces. In this investigation, sensitized phosphorescence decay times in different conditions were measured for naphthalene-biacetyl system in the vapor phase. The ultraviolet-visible spectrum of biacetyl vapor at room temperature conditions was broad and structureless.