Nonradiative processes in p -C6H4F2 and m -C6H4F2

Abstract

The nonradiative lifetimes and quantum yields of individual vibronic levels of m ‐ and p ‐C₆H₄F₂ have been experimentally determined. The data collected for the difluorobenzenes show great differences between the nonradiative decay processes in the para and meta compounds and similarity between these processes in meta ‐difluorobenzene and monofluorobenzene. It is suggested that the differences cited are a consequence of the different molecular symmetries and, as a result, the different possible accepting modes and the manner in which the excess energy distributes itself in the triplet manifold.