Pressure Dependence of Energy Transfer from Pyrene to Perylene

Abstract

The efficiency of singlet‐singlet energy transfer between pyrene and perylene in polymethylmethacrylate decreases with increasing pressure, i.e., at 77°K the critical transfer distance R₀ is 44 Å at 1 atm and 35 Å at 30 kbar. The factors responsible for the reduced efficiency at high pressure are in order of decreasing importance: the decrease in the fluorescence lifetime of the donor, the increase in the refractive index of the medium, and the decrease in spectral overlap of pyrene fluorescence and perylene absorption.