Quasiclassical-trajectory Monte Carlo methods for collisions with two-electron atoms

A quasiclassical-trajectory Monte Carlo (QTMC-EB) model is proposed to extend the classical,trajectory Monte Carlo (CTMC) method to targets having more than one electron. Quasiclassical stability is achieved via constraining potentials that enforce lower energy bounds on the one-electron dynamics. Cross sections for all possible electronic rearrangements (single and double electron transfer, single and double ionization, and transfer ionization) in H++H, H++He, He2++He, and Li3++He collisions are calculated with this model and with the previously proposed model (QTMC-KW) of Kirschbaum and Wilets [Phys. Rev. A 21, 834 (1980)]. The results are compared with accurate experimental data. The regime of validity for the two-electron targets is found to be similar to that of the usual CTMC model for one-electron targets.