Electronic quenching rates for NO(A 2Σ +) measured in a shock tube

Abstract

We report rate coefficients for electronic quenching of NO(A 2Σ +) by NO(X 2Π), CO 2, Ar and He measured at high temperature behind reproducible shock waves. NO and CO 2 are efficient quenchers at temperatures between 300 and 2100 K while the rare gases quench much less efficiently. We develop a model to predict the temperature dependence of NO(A 2Σ +) quenching by collision partners that have a large electron affinity and thereby enable a charge-transfer complex (NO +X −) to mediate the transition between the A 2Σ + ν′ =0 and X 2Π states of NO.