Competition between radiation and photofragmentation in the à 2Σ+ state of the SH/D rare gas complexes

The natural lifetimes of a large number of the vibrational levels of the excited A 2Σ+ electronic state of the family of rare gas complexes, R⋅SH (R=Ne, Ar, and Kr) and their deuterides, are reported. It is well known that the natural lifetime of the A 2Σ+ state of isolated SH/D is markedly shortened by a photofragmentation process. Our results for the complexes show that the rare gas atom plays an important role in inhibiting this process. From a classical model of the molecular system we are able to explain the trends observed in our lifetime data. The data from the R⋅SD complexes where for some vibrational levels the deuterium atom appears to be trapped between the rare gas and sulfur atoms allows us to establish a radiative lifetime for these complexes and the SH/D monomer.