Ultraviolet photodissociation dynamics of H2S and D2S

Abstract

Nascent SH(X 2Π i , v‘=0,1) and SD(X 2Π i , v‘=0,1) rotational state population distributions, spin–orbit state population ratios, and Λ‐doublet state population ratios have been measured following the UVexcimer laserphotodissociation of H2S (λ=193, 222, and 248 nm) and D2S (λ=193 and 222 nm), respectively. Nascent SH(X 2Π i , v‘=0) rotational state distributions following 193 nm photodissociation of cold H2S in a free jet expansion vs 300 K H2S in a flowing gas cell were essentially the same, indicating that photofragment angular momentum must be originating predominantly in the dissociation event, and not from rotational energy contained in the parent triatom. Laser excitation spectra of SH(X 2Π i , v‘=1) and SD(X 2Π i , v‘=1) have been recorded for the first time. Rotational state distributions for SH(X 2Π i , v‘) and SD(X 2Π i , v‘) are independent of v‘. Λ‐doublet population ratios of the nascent photofragments are essentially unity for all the cases measured. The nascent rotational state distributions are consistent with an impact parameter model for the dissociating triatomic molecule.