Theoretical study of the anisotropic interaction potential and partial scattering cross sections for He-HCl system

Abstract

In this paper, an anisotropic intermolecular potential of the He-HCl complex has been obtained by utilizing the BFW analytic function to fit the intermolecular energy data, which have been calculated at the theoretical level of the single and double excitation coupled-cluster method with noniteractive perturbation treatment of triple excitation CCSD(T). Then the differential and partial scattering cross sections for collisions between He atoms and HCl molecules have been calculated by using CC(Close-Coupling) approximation method. Finally, the law governing the changes of the partial scattering cross sections has been given. This study shows that the fitted anisotropic intermolecular potential not only possesses the advantage of a simpler function form but also offers a better description of the characteristic of interaction in He-HCl system. At the same time, the difficult problem to determine the intermolecular potential parameters can be solved on the basis of the results of ab initio calculation for the collision systems. Therefore, the result obtained may be helpful for probing collision mechanism of atoms and molecules.