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

Abstract

The quenching rate constants for $\mathrm{CO}{\mathrm{\hspace{0.17em}(a\hspace{0.17em}}}^3\text{Π; ν′=0,1,2)}$ 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 $\mathrm{CO}{\mathrm{(a\hspace{0.17em}}}^3\mathrm{\Pi )}$ were the interaction of Ar(³P_{0, 2}) or He(2³S) atoms with carbon dioxide. The bimolecular‐quenching coefficients are ${\text{[inverted lazy s] 10}}^{\text{−10}}\hspace{0.17em}{\mathrm{cm}}^3\hspace{0.17em}{\sec }^{\text{−1}}$ , 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 $\mathrm{CO}{\mathrm{(a\hspace{0.17em}}}^3\mathrm{\Pi )}$ . The reaction between ${\mathrm{N}}_2{\mathrm{(A\hspace{0.17em}}}^3{\Sigma }_u^{+}\text{; ν′=0,1)}$ and CO(X) is discussed in an appendix.