A closer insight into classical models for the He atom with two-active electrons

In this work, 2 classical models which had been proposed to describe He atoms in collision processes by charged particle impact are revisited and analyzed. These are the Heisenberg-core and the energy-bounded classical trajectory Monte Carlo methods. These models avoid the classical auto-ionization by introducing in the Hamiltonian momentum-dependent terms. The physical implication of different choices of the involved parameters are analyzed as well as their influence at the total cross section level. We have found that the first and second ionization potential strongly depend on the particular choice of parameters for both models. Such strong dependence reflects in the spatial distribution different models employed highlighting the fact that this channel is fed with events corresponding to inner impact parameters. Present results for the 'single ionisation / single capture' ratios for C⁶⁺ and O⁸⁺ collisions with He, suggest that a correct description of the first and second ionization potentials could be particularly relevant as the projectile charge increases