Rotational energy transfer in collisions between CN (X, ν = 2) and argon. Comparison with results for helium

Transfer of rotational energy in CN (X, ν = 2) in single collisions with argon atoms was investigated, and is compared with our earlier results for collisions between CN (X) and helium. Rates of transfer between individual rotational states and total rates of loss to all other states are determined by using stimulated emission pumping from the ν = 0 level of CN (X). Alternations in the sizes of state-to-state rates, known as the ‘homonuclear propensity’, are compared for collisions with Ar and He. The detailed rate constants are fitted by a power-gap function for both even and odd ΔN transitions.