Vibrational distributions and rate constants from reactions of oxygen atoms with HI, GeH4, SiH4, H2Se, and H2S

Abstract

The OH(v≥0) distributions from the title reactions have been measured in a flowing-afterglow reactor using infrared chemiluminescence and laser-induced fluorescence techniques, which give the OH(v≥1) and OH(v≤1) distributions, respectively. The measured OH(v=0) relative population confirmed previous estimates for OH(v=0) populations based on extrapolations of linear surprisals using a three-body prior. The 〈fV(OH)〉 values closely resemble the 〈fV(HF)〉 and 〈fV(HCl)〉 values from the corresponding F and Cl atom reactions, suggesting similar dynamics for H abstraction by O(3P), F(2P), and Cl(2P) atoms. The room temperature rate constants for OH formation are 4.2±0.5×10−12 (GeH4), 2.1±0.8×10−12 (H2Se), 1.2±0.4×10−12 (SiH4), and ≤3.8×10−14(H2S)cm3 molecule −1 s−1, which are 2–3 orders of magnitude lower than for the corresponding F(2P) and Cl(2P) atom reactions. Formation of OH is not the major product channel from O+PH3; however, for certain conditions there are fast secondary reactions that can lead to strong OH chemiluminescence.