Quenching rate constants for CO(a3Π; ν′=0,1,2)

Abstract

The quenching rate constants for CO (a 3Π; ν′=0,1,2) with H2, D2, N2, O2, NO, CO, CO2, COS, CS2, SO2, NH3, C2N2, CH4, C2H2, C2H4, C2H6, C2F6, and SF6 have been measured in a discharge-flow apparatus. The sources of CO(a 3Π) were the interaction of Ar(3P0, 2) or He(23S) atoms with carbon dioxide. The bimolecular-quenching coefficients are [inverted lazy s] 10−10 cm3 sec−1, except for N2, CO2, C2F6, and SF6, which range from 10−11 to 10−12 cm3 sec−1. Only the rate constants for N2, CO, and CS2 showed a dependence upon the vibrational excitation of CO(a). For these reagents, the mechanism for quenching is discussed; the reaction with N2(X) yields significant amounts of N2(A). The CO(a) + NO(X) reaction is of particular interest because the β- and γ-band emission can be used to identify the NO(A and B) products and to provide a diagnostic test for the presence of CO(a 3Π). The reaction between N2(A 3 Σu+; ν′=0,1) and CO(X) is discussed in an appendix.