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: B_e′=8.538₁ cm⁻¹, α_e′=0.509₁ cm⁻¹, r_e′=1.421₅A, ν₀₀=30,662.4₂ cm⁻¹, ΔG_½′=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.