Competition between radiation and photofragmentation in the (A)over-tilde2Σ+ state of the SH/D rare gas complexes

The natural lifetimes of a large number of the vibrational levels of the excited (A) over tilde (2)Sigma(+) 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) over tilde (2)Sigma(+) 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 fur these complexes and the SH/D monomer. (C) 1998 American Institute of Physics. [S0021-9606(98)00925-5].