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The reaction dynamics of H+H2S→H2(v, J)+SH was studied under a low-pressure bulk condition. Fast H atoms were generated by ArF laser photolysis of H2S and H2 products were detected by vacuum ultraviolet–laser-induced fluorescence (VUV–LIF) on the B 1 Σ + u – X 1 Σ + g transition. The Doppler profiles of some rotational lines of v=2 and v=3 were analyzed to determine the translational energy of H2. Although the measurements were carried out at a single geometry of the photolysis and probe lasers, the results indicate that H2 has high translational energies with narrow widths. The suggested mechanism is a direct mechanism where the H atom picks up the terminal H and SH is almost a spectator.

Vacuum ultraviolet photodissociation dynamics of CH3CN and CD3CN has been studied at wavelength near the Lyman-α transition (121.6 nm). Two products, CN(B 2Σ) and H or D, were observed. The CN(B 2Σ–X 2Σ) chemiluminescence spectrum was analyzed to determine vibrational and rotational distributions of CN(B). The vibrational distribution was Boltzmann-like and agreed with a statistical distribution. Although the rotation of the v=0–3 states were also characterized by the Boltzmann distribution, the average rotational energy was higher than the statistical energy disposal. The line shape of the Lyman-α laser-induced fluorescence of H and D showed a Gaussian Doppler profile, which was ascribed to the statistical translational energy distribution of H and D. Isotope effects were determined for both products. While no isotope effect was observed for energy partition into the vib-rotation of CN(B) and the translation of H and D, relative yields of two products showed an isotope effect, i.e., CN(B) formation was f...