On the generation of preferential Λ‐doublet populations in the collisional relaxation of highly rotationally excited CH(X 2Π)

摘要: By means of full quantum close‐coupling and coupled states calculations based on an ab initio potential energy surface for the Ar–CH system, we confirm a propensity seen experimentally by Hancock, Stuhl, their co‐workers. During rotational relaxation high levels CH(X 2Π) radical, produced photolysis suitable precursor, there appears clear population imbalance in favor Λ‐doublet Π(A‘) symmetry. A kinetic simulation, calculated cross sections, reproduces nearly quantitatively experimental observations both temporal evolution pressure dependence this asymmetry. This asymmetry is consequence enhanced depletion N Π(A’) formation next lower (N−1) manifolds. The physical origin involves crossing between two adiabatic bender potentials which follow, respectively, A’ A‘ (PES). crossing...