Fluorescence lifetimes of single vibrational levels in HSO (Atilde;thinsp;2Aprime;)

摘要

Fluorescence lifetimes of single vibrational levels of the first excited state of HSO and DSO have been measured under effusive flow conditions following excitation by a pulsed dye laser. The lifetimes show a systematic decrease withvprime;3(Sndash;O stretch) from 74 mgr;s (vprime;3=1) to 26 mgr;s (vprime;3=8) for HSO. For DSO, the lifetimes are longer than the corresponding ones of HSO. These results are interpreted in terms of a secondhyphen;order coupling model (Atilde;thinsp;2Aprime;rarr;Xthinsp;2Aprime;prime;rarr;continuum) in which the final states are those of H+SO dissociation continuum. An analytical expression is given to compute the vibrational energy dependence of nonradiative rates assuming an energy dependent linewidth from the dissociation.