Kinetics of the reactions of methylene (X3B1)-radicals with nitric oxide and nitrogen dioxide

Abstract

The kinetics of the reactions of CH{sub 2} radicals in their triplet electronic ground state ({tilde X}{sup 3}B{sub 1}) with NO and NO{sub 2} (CH{sub 2}({tilde X}{sup 3}B{sub 1}) + NO {yields} products (1); CH{sub 2}({tilde X}{sup 3}B{sub 1}) + NO{sub 2} {yields} products (2)) have been studied at room temperature in isothermal discharge flow systems. CH{sub 2} radicals were generated either by exciplex laser photolysis of CH{sub 2}CO or via the reaction O + CH{sub 2}CO {yields} CH{sub 2} + CO{sub 2}. The CH{sub 2} concentration was monitored directly with a far-infrared laser magnetic resonance spectrometer. From the decay of (CH{sub 2}) under pseudo-first-order conditions the rate constants of reactions 1 and 2 were obtained to be k{sub 1}(296K) = (2.2 {plus minus} 0.5) {times} 10{sup 13} cm{sup 3}/(mol s) and k{sub 2}(296K) = (5.9 {plus minus} 1.4) {times} 10{sup 13} cm{sup 3}/(mol s).