An anisotropic intermolecular potential of the He-HF 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). And the reliability of the potential has been verified by comparing it with other potential models. The differential, partial and total scattering cross sections for collisions between He atoms and HF molecules have been calculated respectively by using the quantum close-coupling method at five different potential models, and the calculated results have been compared and analysed in detail. The research shows that the scattering cross sections are sensitive to the position where potential is zero, the well depth, the strength of the repulsive wall of the spherically averaged and to the anisotropy of the region of the well depth. We hope that the results can provide profitable reference for determining exactly the interaction potential of the atomic-molecular collision systems from the scattering cross sections.

For the first time, the elastic, inelastic and total differential cross sections for collision between He atom and the ground state of BH molecule have been calculated by using accepted exact close-coupling approximation method. The calculation is performed at the incident energies from 25 to 150 meV. Further, the change tendency and characteristics of the differential cross sections have been discussed. The calculated results show that the total differential cross section is the general rule and characteristics of collision between an atom and a diatomic molecule, the phenomenon of the scattering oscillation at large angles is more evident along with increase of the incident energy for low-lying rotational excitation state-to-state differential cross sections in He-BH collision system.

An anisotropic intermolecular potential of the He-NO complex has been obtained by utilizing the Huxley analytic function to fit the intermolecular energy data, which have been calculated at the theoretical level of the RCCSD(T)/aug-cc-pVTZ+bf. Then the total differential cross section, elastic differential cross section and inelastic differential cross section for collision between He atom and NO molecule have been calculated using close-coupling approximation. Finally, the law governing the change of the differential scattering cross section 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-NO system. At the same time, the difficult problem of determining 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 between atoms and molecules.

Close-coupling method was applied to the 3He（4He,5He）-H2 system, and the second vibrational excitation cross sections of “00-20，00-22，00-24，00-26” at different incident energies have been calculated．By analysing the differences of these partial wave cross sections, the change rules of how the partial wave cross sections change with the mass of isotope atom and the relative kinetic energy of incident atoms are obtained.

In this paper，the structures and potential energy functions of the ground states of BeH, BeD, BeT molecules are investigated by quantum mechanical ab initio method in the level of QCISD(T)/aug-cc-pVTZ and CCSD(T)/6-311++G(3df，2pd). The spectroscopic data, ωe，ωeχe，Be，αe and De for the ground states obtained from the calculation are in good agreement with the data from experiment. It indicates that the potential energy functions of BeH, BeD, BeT can be expressed by the corrected Murrell-Sorbie functions.