Classical simulation of spin-tagged collisional ionization at near-threshold energies

In this paper, we develop a spin dependent classical trajectory Monte Carlo approach to investigate the spin-tagged collisional ionization process. With the help of anti-symmetrized Gaussian wave packets, an effective interaction potential between the two spin-tagged electrons is derived to mimic the spin associated quantum effect of Pauli exclusion principle. Our model is applied to investigate the spin dependent collisional ionization of e–H system. The results are in good agreement with experimental data, ab initio quantum-mechanical calculations as well as a variety of characteristics of the Wannier theory for near-threshold ionization. In contrast, the popular Fermionic molecular dynamics model overestimates the total ionization cross section as high as ten times and predicts a totally inversed ionization spin asymmetry contrary to experimental results. Further applications of our model to laser-assisted collisional ionization are demonstrated and some interesting results are presented. (paper)