Quantum Mechanics Of Atomic And Diatomic Molecular Collision Processes

There are two parts in this dissertation. In part one, the reaction scattering for the H3 system is studied using three-dimensional quantum mechanical coupled channel distorted wave approximation. In part two, a new form is proposed for interaction between an atom and a diatomic molecule.Using three-dimensional quantum mechanical coupled channel distorted wave approximation (CCDWA), the reaction scattering H+H2-H2+H, D+H2-DH+H, H+D2-DH+D are studied by employing the three potential energy surfaces, i.e. LSTH, BKMP and PK in part one. The integral, differential, partial wave cross sections and reaction probabilities are calculated for the three collision systems. It is shown that the results calculated using the CCDWA are agreement with one of the accurate quantum mechanics employing the same potential. Quantum mechanical tunneling is important in near threshold, and classical trajectory calculation is not good for prediction of the cross sections. The reaction cross sections calculated using different potentials is different, which show that the investigation of reaction cross section can provide evidence for test of accuracy of the potential energy surface.Firstly, the MS (Maitland-Smith) potential model is improved in part two. The model possesses advantages of the simpler functional representation, the fewer adjustable parameters, the more flexible form, and it is easy to apply. Secondly, the new anisotropic potential energy surfaces are proposed for the He-HF and He-CO systems respectively based on the improved potential model. The potentials are very similar to the accurate SAPT (for the He-HF) and XC (for the He-CO) potentials and can describe exactly the basic characteristic of interaction for the systems. Thirdly, a new anisotropic potential energy surface is presented for the He-NO system according to the MS potential model. The potential is not only quite agreement with the accurate ESMSV potential for the system, but also has the same form and part parameters for the MS potentials of other rare gases (Ar, Kr, Xe) with NO molecule. Finally, an analytical expression is given out using the unproved potential model based on Faubel's calculated data of radial coefficients of interaction for the He-O2 system, the results calculated using the analytical expression is quite agreement with Faubel's calculated data.