Ion scattering from state-selected Rydberg atoms

Classical-trajectory Monte Carlo calculations have been performed for collisions of protons with state-selected hydrogenic Rydberg atoms. The examples investigated were Rydberg atoms in the $n=10$, $l=9$ level with mₗ=0 and 9. The collision velocity range was 0.1 to 1.0 a.u. (2.2×{}10⁷ to 2.2×{}10⁸ cm/s). The ionization cross sections were found to be relatively insensitive to changes in the mₗ levels. However, the charge-transfer cross sections showed considerable enhancement if the Rydberg electron is orientated in a plane which is parallel to the direction of the incident projectile.