A Study of the Reaction of CH₂(ã¹A₁) with H₂O in the Gas Phase

Abstract

Abstract The reaction: was investigated in a quasistatic flash photolysis system at room temperature in the pressure range 0.5 ≦ p /mbar < 1.5 with He as the main carrier gas. The concentrations of CH 2 (ã 1 A 1 ) produced in laser photolysis of CH 2 CO at λ L = 308 nm, and the absolute concentration of the reaction product OH were monitored by laser induced fluorescence. In addition the population of the rotational states of the initial product OH (X, n̈ = 0, K) was measured. The time delay between photolysis and probe pulse delivered the time resolution. — The overall 1 CH 2 depletion rate determined from Stern‐Volmer plots is k 1 (298 K) = (1.3 ± 0.2) · 10 14 cm 3 /mol s. The channel: is determined to be the dominant reaction path in the range 0.5 ≦ k 1a / k 1 ≦ 1.0. The physical deactivation is found to be less than 50% of k 1 , in agreement with previous measurements. The bearing of these results on the reaction CH 3 + OH and on the thermal CH 3 OH dissociation is briefly discussed.