Rate constants for total relaxation from the rotational levels J=7.5, 20.5, 31.5 and 40.5 in NO(X 2Π1/2, v=2) in collisions with He, Ar and N2: a comparison between experiment and theory

Using the infrared–ultraviolet double resonance (IRUVDR) technique, rate coefficients have been measured for the relaxation of NO( X2Π1/2, v=2, J=7.5, 20.5 and 31.5) in collisions with He, Ar, N2 and NO itself. For relaxation from levels J=31.5 and 40.5, rates were measured by a new method in which the IRUVDR method was implemented instantly on NO molecules formed by photodissociation of NO2 at 355 nm. The rate coefficients for collisions with He, Ar and N2 are found to decrease at high J, with the decrease least with He. The experimental results for NO–He and NO–Ar are shown to agree well with those from coupled states quantum scattering calculations on ab initio potential energy surfaces.