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

Abstract

Rate constants for H-atom attack on PH ₃ and AsH ₃ have been measured in flash photolysis experiments in which H atoms were generated by the Hg-sensitised photolysis of H ₂ and monitored by Lyman-α absorption. The values obtained for PH ₃ , in the temperature range 293472 K, are given by k ₁ /cm³ s⁻¹ = (1.09 ± 0.08) × 10⁻¹⁰ exp[(−1048 ± 27)/T]and for AsH ₃ , in the temperature range 294–424 K, by k ₂ /cm³ s⁻¹ = (2.57 ± 1.30) × 10⁻¹⁰ exp[(−718 ± 160)/T]An evaluation of the available data on H + PH ₃ has been carried out, and the best value for the rate constant over the temperature range 200–500 K is recommended to be k ₁ /cm³ s⁻¹ = (0.721 ± 0.041) × 10⁻¹⁰ exp[(−887 ± 19)/T]