OSCILLATORY ALIGNMENT PHENOMENA IN RYDBERG-ATOM-RARE-GAS COLLISIONS

Retention of orbital alignment during near-resonant energy transfer co llisions of race-gas projectiles with excited alkaline-earth-metal ato ms is explored theoretically for scattering of Xe from Rydberg states of Ca. For such collisions, conventional interpretations of alignment phenomena, which are based on potential curves for a transient molecul e thought to form during the collision, are not relevant. Theoretical partial magnetic sublevel cross sections for Ca*(4s17d D-1(2)-->4s18p P-1(1)) transitions confirm the existence of alignment effects, as de monstrated experimentally by Spain et al. [J. Chem. Phys. 102, 9532 (1 995)], at a mean relative velocity of 914 m/s. Theory further predicts heretofore unobserved oscillatory structures in these cross sections as a function of relative velocity and that these oscillations depend strongly on the initial magnetic quantum number of the Rydberg electro n. [S1050-2947(98)50301-0].