CLASSICAL-THEORY OF L-CHANGING TRANSITIONS IN COLLISIONS BETWEEN RYDBERG ATOMS AND IONS

The l-changing transitions in collisions of Rydberg atoms with ions, A(nl(0))+B+-->A(nl)+B+, are considered within the classical approximation for atomic electron motion. The elliptic orbit of the electron evolves slowly under the influence of the time-dependent electric field exerted- by the incident ion. The quantum electron state is represented by an ensemble of classical trajectories. Within the dipole approximation extremely simple analytical formulas for the final-state l-distribution function are obtained for a fixed value of the impact parameter. The influence of the non-coulomb core is taken into account approximately. The results of our calculations compare favorably with recent experimental data for the Na+(26d, 28d) Rydberg atom. The method can be extended to the calculation of distributions over various observables other than l.