Density matrix theory and computational aspects of atomic collisions including spin-orbit recoupling

A first principles description of electronic excitation and spin-orbit recoupling in alkali-rare-gas atom colliding pairs is developed introducing 1-dependent pseudopotentials and including two and three-body polarization terms and the spin-orbit interatomic potential. The treatment combines an eikonal (or short wavelength) approximation for the nuclear motion and time-dependent molecular orbitals to provide interatomic potentials, their non-adiabatic couplings, and state populations during interactions.; Our pseudopotential choice is adequate for these systems in terms of accuracy. A description of the matrix equations and computational details of the pseudopotential code are presented. Results on ionization energies of the Li and Na atoms and the potential energy functions of distance for LiHe, LiNe, NaHe and NaNe are presented. Our results are in excellent agreement with experiment and other theories.; The theory of the eikonal time-dependent molecular orbital (Eik/TDMO) method in terms of pseudopotentials is presented as well as a detailed description of the computational approach. We study the time-dependence of orbital alignment, orientation and population. We discuss the effects of the basis set size on the calculations, and compare our results with experiment and other calculations. Our integral cross sections for LiHe, LiNe, NaHe and NaNe, obtained with a large basis set, are in excellent agreement with experiment.; The theory for recoupling of angular momenta in alkali-rare-gas atom thermal collisions is developed and the computational aspects of the spin-orbit coupling code in terms of pseudopotentials are presented. Results for the spin-orbit splitting of the 2P states of Li and Na are presented along with fine-structure cross sections for collisions at 400 and 450 K. The agreement with experiment and other theories is very good.