Theoretical calculation of the vib-rotational interaction potential and the partial wave cross sections for He-H 2 (D 2 , T 2 ) system

The interaction potential surfaces of He-H 2 (D 2 , T 2 )have been calculated by employing supermolecule method and the single and double excitation coupled-cluster with a noniterative perturbation treatment of triple excitation CCSD(T) approach using a large basis set containing the atomic centre Gaussian function and the 3s3p2d1f key function when the key-lengths of H 2 was different. The vib-rotational interaction potentials of He-H 2 (D 2 , T 2 )system were fitted using the Tang-Toennies potential function and nonlinear least square method in a center of mass coordinate system. The partial wave cross sections at the energies of 60,90 and 120 meV have been calculated by using the quantum close-coupling method. On the basis of the above results, the change rules of the partial wave cross sections with change of quantum number have been obtained. Furthermore, corresponding connection and scattering characteristics of partial wave cross sections and scattering parameter were discussed in combination with classical collision theory.