Collision-induced rotational energy transfer of CO (A1Π,v=3) with He, Ne and Ar: (II) theoretical interpretation of the experiment

To interpret theoretically our previous experiment [Chem. Phys. Lett. 365 (2002) 244], a theoretical model is presented, based on the time-dependent first order Born approximation, taking into account the anisotropic Lennard–Jones interaction potentials and ‘straight-line’ trajectory approximation. Quantum interference of Π-state diatomic molecules, which originates from the difference between the two Λ-related collision potential energy surfaces, is studied theoretically. Using our derived results, three phenomena are interpreted: (1) cross-sections σ(Π+)>σ(Π−), (2) the propensity of +/− parity-conservation, and (3) the abnormal phenomenon of σΔJ=0ε→ε′<σΔJ=±1ε→ε′ for He and Ne.