Collisional quantum interference on rotational energy transfer: physical interpretation of the interference angle Original Research Article

A dynamic model of collisional quantum interference (CQI) on rotational energy transfer in an atom–diatom system is presented, based on the first-order Born approximation of time-dependent perturbation theory and the long-range interaction potential. The interference angle, proposed by Sha, is described theoretically. The relation between the differential and the integral interference angle is shown. The key factors that the interference angle depends on are obtained. When the integral interference angle θSTI=90° or 0°, this model is the “gateway” model proposed by Gelbart and Freed or the `complete coherenceʹ model proposed by Alexander, respectively. If the quadrupole and dipole–quadrupole polarizibilities are not considered, i.e., Θ=0 and β=0, this model is the model proposed by Sun, which has been used to simulate the CO (A1Π–e3Σ−)–He experiment, and the calculated values are consistent with the experimental results. Moreover, this model can also be used to simulate molecular beam experiments to calculate differential cross-sections and differential interference angle.