Absorption Spectra of SH and SD Produced by Flash Photolysis of H2S and D2S

Abstract

H2S and D2S were irradiated in a flash photolysis apparatus, and the absorption spectra of the products were photographed within 1 millisecond of the photolysis flash using the second order of a 21 ft grating spectrograph. The (0,0) and (1,0) bands of SH and SD were observed and analyzed. The following molecular constants for SH were obtained: 2Σ+ state: Be′=8.5381 cm−1, αe′=0.5091 cm−1, re′=1.4215A, ν00=30,662.42 cm−1, ΔG½′=1784.63 cm−1, γ0=0.313 cm−1. 2Π state: B0″=9.4611 cm−1, r0″=1.3503A, A=−376.96 cm−1. The rotational lines of the (1,0) SH band were observed to be diffuse, indicating a predissociation in the first vibrational level of the 2Σ+ state. This establishes an upper limit of 92.7 kcal and a lower limit of 66.3 kcal for the ground state dissociation energy of SH.