Calculation of transition probabilities for collinear atom–diatom and diatom–diatom collisions with Lennard-Jones interaction

Numerical integration of the close coupled scattering equations is performed to obtain vibrational transition probabilities for three models of the electronically adiabatic H2-H2 collision. All three models use a Lennard-Jones interaction potential between the nearest atoms in the collision partners. The results are analyzed for some insight into the vibrational excitation process, including the effects of anharmonicities in the molecular vibration and of the internal structure (or lack of it) in one of the molecules. Conclusions are drawn on the value of similar model calculations. Among them is the conclusion that the replacement of earlier and simpler models of the interaction potential by the Lennard-Jones potential adds very little realism for all the complication it introduces