An examination of the use of vibrationally adiabatic basis functions for the calculation of molecular collision cross sections

摘要: Comparison is made between the use of two different types vibrational basis functions for expansion total wave function in a vibrationally inelastic scattering problem. The calculations are performed within framework sudden approximation rotational motion molecular fragments. that compared adiabatic set and standardly used diabatic functions. chosen so as to approximately diagonalize matrix representation interaction potential at each value coordinate. Nevertheless, they permit formulation analytic expressions nonadiabatic coupling terms kinetic energy operator present when an used. In order provide reference against which judge bases, sets coupled differential equations arise solved He+H2 system, fixed‐angle S matrices calculated several energies values angular momenta. It shown if customary conjunction with first distorted perturbation theory calculate matrices, these do not agree well exactly computed should correspond. contrast, used, yields good agreement (within 15% or better) fully converged exact calculations.