Radiative and Nonradiative Decay of Electronically Excited HNF and DNF

Abstract

AbstractDecay lifetimes for a range of HNF and DNF levels in their excited à 2A' electronic states, in specific K' stacks and in some cases in individual N' rotational levels, are reported. Above a threshold energy, these lifetimes are found to drop, in a K'‐ and N'‐dependent way, below the extrapolated purely radiative lifetimes. This reduction in lifetime is ascribed to the onset of nonradiative, predissociative decay. Lifetimes for individual N' rotational levels in the HNF(Ã2A') (0,4,0) and DNF(Ã2A') (0,6,0) vibrational manifolds are also reported. These are found to fluctuate in a seemingly random manner vs. N', reflecting the variation of the coupling to the dissociation continuum. The implications of these results and, from other experiments, the direct observation of NH(X3Σ−) and ND(X3Σ−) photofragments for the dynamics of the nonradiative decay of electronically excited HNF and DNF are discussed.