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(4P5/2)]â†� P[3p3(4S)]}. Second-order absolute rate constants are reported for the following reactant gases (R)(kR/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(32DJ) and P(32PJ), 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.