Ultraviolet photodissociation dynamics of H2S and D2S

Authors

Brad R. Weiner, Naval Research LaboratoryFollow
Harold B. Levene, Naval Research Laboratory
James J. Valentini, Naval Research Laboratory
A. P. Baronavski, Naval Research LaboratoryFollow

Date of this Version

1988

Citation

J. Chem. Phys. 90 (3), 1 February 1989,

Abstract

Nascent SH(X² Π_i, v" = 0,1) and SD(X² Π_i, v" = 0,1) rotational state population distributions, spin-orbit state population ratios, and A-doublet state population ratios have been measured following the UV excimer laser photodissociation of H₂S (λ = 193, 222, and 248 nm) and D₂S (λ = 193 and 222 nm), respectively. Nascent SH(X² Π_i, v" = 0) rotational state distributions following 193 nm photodissociation of cold H2 S in a free jet expansion vs 300 K H2 S 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(X² Π_i, v" = 1) and SD (X² Π_i, v" = 1) have been recorded for the first time. Rotational state distributions for SH(X² Π_i, v") and SD(X² Π_i, v") are independent of v". A-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.