Reaction of Molecular Sulfur in the Electronically Excited State S 2 ( a 1 Δ g ) with Hydrogen Sulfide

The potential energy surface for the S_2( a^1Δ_g) + H_2S→SH + HS_2. reaction is calculated in the formalism of the extended multi-configuration quasi-degenerate perturbation theory (XMCQDPT2). The found geometric parameters and frequencies of normal vibrations of stable intermediates and transition states are used to estimate the effective reaction rate constant in the transition state theory for the temperature range of 500 to 2000 K. The form of the Arrhenius dependence is found for the rate constant.