Arrhenius parameters for the reactions of H atoms with PH₃ and AsH₃

Abstract

Rate constants for H-atom attack on PH₃ and AsH₃ have been measured in flash photolysis experiments in which H atoms were generated by the Hg-sensitised photolysis of H₂ and monitored by Lyman-α absorption. The values obtained for PH₃, in the temperature range 293472 K, are given by

k₁/cm³ s⁻¹ = (1.09 ± 0.08) × 10⁻¹⁰ exp[(−1048 ± 27)/T]

and for AsH₃, in the temperature range 294–424 K, by

k₂/cm³ s⁻¹ = (2.57 ± 1.30) × 10⁻¹⁰ exp[(−718 ± 160)/T]

An evaluation of the available data on H + PH₃ has been carried out, and the best value for the rate constant over the temperature range 200–500 K is recommended to be

k₁/cm³ s⁻¹ = (0.721 ± 0.041) × 10⁻¹⁰ exp[(−887 ± 19)/T]