Energy transfer processes in reactions of He(23S) with triatomic molecules. II. H2O and H2S

The energy transfer reactions He(2³S) + H₂O and He(2³S) + H₂S were studied spectroscopically in the visible and ultraviolet ranges in a flowing afterglow apparatus. No primary triatomic ion emission was observed in this study. Only dissociative fragments were found to emit. In the He(2³S)/H₂O system intense OH(A²Σ⁺ → X²Π_i) emission bands and hydrogen Balmer series were observed while in the He(2³S)/H₂S system intense HS⁺(A³Π_i → X³ Σ^?), weak hydrogen Balmer series and some atomic sulfur lines were found. It is concluded that dissociative processes are competitive with Penning ionization in these energy transfer reactions with other possible reaction channels playing inferior roles. The post-ionization process of ion—electron recombination in the flowing afterglow dominates the emission results in the He(2³S)/H₂O system.