CLASSICAL CHARGE-TRANSFER AND IONIZATION CHANNELS FOR ION COLLISIONS WITH CIRCULAR RYDBERG ATOMS

Explorations of the classical phase space for ion collisions with circular Rydberg atoms are presented. Intermediate-energy capture and ionization processes are studied through the numerical integration of Newton's equations of motion and through the graphical depiction of the outcomes of large numbers of trajectories. Maps which correlate initial conditions with final outcomes are used to identify zones of parameter space leading to Thomas capture, direct capture, binary-encounter ionization, saddle-point ionization, and ionization by S superpromotion (E. A. Solov'ev, Zh. Eksp. Teor. Fiz. 81, 1681 (1981) [Sov. Phys. JETP 54, 893 (1981)]). Charge-transfer channels in which the electron passes once or three times through the midplane between the nuclei are shown to occur in separate zones of parameter space over the entire range of projectile speeds above the mean velocity of the target electron. © 1995 The American Physical Society.