Fluorescence lifetimes and predissociation of the A3? state of SH+

Abstract

The high frequency deflection (HFD) technique has been used to obtain fluorescence lifetimes of the SH+ A3Π state. The A3Π−X3∑− electronic transition moment function has been calculated with the complete active space SCF(CASSCF) method. Radiative lifetimes calculated with this transition moment function are compared with measured lifetimes and found to be in good agreement (τexp(v′=0)=1.4±0.3 µs; τcalc=1.6 µs). Deviations between measured and calculated lifetimes forv′=0,J′ ≥ 15 andv′=1,J′=1−7 are interpretated as due to a predissociation caused by a repulsive5∑− state. A simple model, based on a perturbation approach to the predissociation, is used to obtain quantitative estimates of predissociation rates. These calculated rates are in reasonable agreement with the predissociation rates that are inferred from the measured and calculated lifetimes.