A low pressure (1-8 torr of He) discharge flow reactor with (a) LIF detection of SH using a high repetition rate (20 kHz) metal atom laser to circumvent severe predissociation of the A2Σ+ state and (b) resonance fluorescence detection of OH has been used to examine the kinetics of the title reactions at 298 K: SH + NO2 → HSO + NO, k1 = (3.0 ± 0.8) × 10-11 cm3 s-1; SH + O3 → HSO + O2, k2 = (3.2 ± 1.0) × 10-12 cm3 s-1; SH + O2 → SO + OH, k3 < 1 × 10-17 cm3 s-1; SH + H2O2 → H2S + HO2, k4a; SH + H2O2 → HSOH + OH, k4b; SH + H2O2 → HSO + H2O, k4c. k4 = k4a + k4b + k4c < 5 × 10-15 cm3 s-1. Regeneration of SH in reaction 2 by HSO + O3 is observed and is used to infer a rate constant for HSO + O3 → products of (1.0 ± 0.4) × 10-13 cm3 s-1. Absence of OH production in that reaction implies that the primary products are SH + 2O2. Isotope experiments with H2S replaced by D2S substantiate that conclusion and yield a reaction rate constant for DSO + O3 → SD + 2O2 of 9 × 10-14 cm3 s-1. Brief discussions of SH reactivity compared with OH and Br are offered, as well as a summary of the atmospheric chemistry of SH.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry