Kinematic effects in rotationally inelastic A + BC collisions

Three-dimensional quasiclassical trajectory results obtained using an ab initio potential energy surface for rigid rotor HFLi collisions exhibit an interesting kinematic effect: with increase in mass of the projectile atom the amount of rotational energy transferred decreases in contrast to the reverse trend known in homonuclear diatom-atom collisions. The differing kinematics effects are explained on the basis of differing effective anisotropies that become evident in plots of potential energy contours in mass-weighted coordinates (R, δ) proposed recently by Loesch. We also work out the conditions for multiple collisions using different ellipse models.