Classical charge transfer and ionisation cross sections for one- and three-dimensional collision processes

The wavefunction associated with the classical trajectory Monte Carlo method is calculated for a one-dimensional collision model, and the resulting transition probabilities are compared with those obtained with the exact wavefunction. It is shown that if the transition amplitude per unit time is integrated, the classical wavefunction provides the correct behaviour of the transition probabilities at high projectile velocities. We also present CTMC (classical trajectory Monte Carlo) total ionisation and capture cross sections for fully stripped light ions colliding with H and He+ targets, computed with an initial distribution that exactly reproduces the quantum probability density of the electronic coordinate. The results are compared with those obtained with the usual microcanonical distribution and with experimental data. (author)