Diatomic Molecule Potential Energy Function And Vibrational Excitation Scattering Theory

There are two parts in this dissertation. In part one, an analytical potential energy function of a diatomic system is constructed using energy consistent method (ECM), and part two studies the low-energy electron scattering from N2 molecule based on the body frame vibrational close-coupling (BFVCC) equation.Using the second order perturbation theory, the formulae of vibrational force constants are derived in part one. Then, a new analytical potential energy function of diatomic molecule is proposed based on the ECM and applied to some electronic ground states and excited states of diatomic molecules. The results are shown that the new potential not only satisfies the correct physical properties, but also has excellent accuracy in both the repulsive and attractive branches, particularly for the molecular electronic excited states.In the beginning of part two, the vibrational close-coupling equation of low-energy electron scattered by diatomic molecule and the calculating method of the interaction potential are introduced. Allowing for the influence of non-adiabatic effects, a new polarization potential is proposed on the basis of spherical Gauss charge distribution (SGCD) model. .The SGCD polarization potential shows the non-adiabatic effect at the "intermediate" region and can be reverted to the adiabatic polarization potential at the long-range region. The static and the SGCD polarization potentials between a scattered electron and N2 molecule are calculated using ab initio method and the vibrational closed-coupling potentials are generated using the ECM vibrational wavefunctions. At last, the integrated and differential cross sections of v = 0 → 0, v = 0 →1 scattering processes are studied using BFVCC equation and the comparisons with the experiment are found to be very satisfactory.