Influence of Temperature on the Removal Rates of CH2(ã1A1 ) by Inert Gases and Hydrocarbons

Abstract

Abstract The reactions of CH2(ã1A1) with the inert gases He, Ar, N2 , with H2 and with the hydrocarbon reactants CH4 , C2H6 , C2H4 and C6H6 have been investigated at 210, 295 and 475 K. CH2(ã1A1) was generated by pulsed laser photolysis in a quasistatic thermostated gas cell and detected by pulsed laser induced fluorescence. Concentration profiles of CH2(ã1A1) were recorded under first order reaction conditions by varying the time delay between the photolysis and the probe laser pulses. The second order rate constants determined at room temperature are in good agreement with those of earlier work. No differences between the removal rates of ortho-and para-methylene nuclear spin states by the inert gases were observed. The experimental rate constants were fitted to an expression k = A -(77295 K)n. The results are given in the form {A ± AΔA} {n ± Δn) with A in units of 1013 cm3/mol • s: