Spin-orbit recoupling in alkali-rare-gas atom colliding pairs is developed within a first principles description of the quantum dynamics introducing l-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 nonadiabatic couplings, and state populations during interactions. The time evolution of recoupling of angular momenta in alkali-rare-gas atom thermal collisions is described and computational aspects of spin-orbit coupling in terms of pseudopotentials are presented. Results for potentials arising from the spin-orbit splitting of the P-2 states of Li and Na are presented along with cross sections for fine-structure transitions at 400 K and 450 K. The agreement with experiment and other theories is very good. (C) 2003 American Institute of Physics.