Reactions of phosphorus atoms, P(34S), studied by attenuation of atomic resonance radiation in the vacuum ultraviolet

Abstract

Kinetic studies are described for the reaction of ground state phosphorus atoms, P(3⁴S), with a number of different gases. P(3⁴S) was generated by the repetitive pulsed irradiation of PCl₃ in the presence of excess helium buffer gas and monitored photoelectrically in absorption by time-resolved attenuation of atomic resonance radiation in the vacuum ultraviolet at λ= 177.50 nm {P[4s(⁴P_5/2)]â†� P[3p³(⁴S)]}. Second-order absolute rate constants are reported for the following reactant gases (R)(k_R/cm³ molecule^–1 s^–1, 300 K): H₂(< 5 × 10^–15), O₂(2.0 ± 0.1 × 10^–12), NO (4.3 ± 0.1 × 10^–13), Cl₂(3.9 ± 0.05 × 10^–12), CO (< 5 × 10^–15), CO₂(<5 × 10^–15), N₂O (⩽ 5 × 10^–15), NH₃(<5 × 10^–15), C₂H₂(4.4 ± 0.3 × 10^–13), C₂H₄(2.1 ± 0.2 × 10^–12), C₂H₆(< 5 × 10^–15) and PCl₃(2.5 ± 0.05 × 10^–11). These rate data are compared, where appropriate, with the analogous data for P(3²D_J) and P(3²P_J), and those for N(2⁴S), and discussed within the context of the nature of potential surfaces derived from symmetry arguments using the weak spin orbit coupling approximation.