The electronic quenching rates of NO(A2Σ+, v′=0-2)

The electronic quenching rates of NO(A(2)Sigma(+), v' = 0-2) are measured for the gases He, Ar, Xe, N-2, O-2, CO2, N2O, and SF6. The variations of the fluorescence intensity were measured for the (0,0), (1,0), and (2,0) bands of the gamma band system when the quencher gases were added. The quenching rates were determined by using the Stern-Volmer plots with the known radiative lifetimes of the excited states. The electronic quenching rate constants are fast for the group of gases of O-2, CO2, N2O, and SF6, whose quenching rate constants are in the order of 10(-10) cm(3)/s. The quenching rate constants are slow for the group of gases including He, Ar, Xe, and N-2 whose rate constants are in the order of 10(-14) cm(3)/s. For the slow group, the quenching rate constants increase rapidly for v' = 2 compared with those of v' = 0 and 1. The charge transfer model and collision complex model are used to understand the quenching mechanism. For the fast group which mainly consists of gases with positive electron affinities, the charge transfer model adequately describes the mechanism. For the slow quenching group, a theoretical background is provided by consider the coupling of initial and final states in the complex potential surfaces. (C) 2004 Elsevier B.V. All rights reserved.