Calculation of three dimensional cross-sections for the Ar-N-2 system fromtwo-dimensional coupled equations plus a three-dimensional boundary condition

A method was recently proposed for calculating state-to-state rotational to tal cross-sections that involves solving two-dimensional close-coupled equa tions but takes into account the three-dimensional boundary condition. In t his Letter, this proposal is tested on the system Ar-N-2 for a range of pot ential parameters that control the anisotropy of the system. In particular, the contribution of the long-range force to the cross-sections is investig ated. The results are in very good agreement with the three-dimensional clo se-coupling calculations in the case that the molecule is initially not rot ating. In all other cases the results are less satisfactory. (C) 2000 Elsev ier Science B.V. All rights reserved.