Collisions of rubidium Rydberg-state atoms with ammonia

Abstract

Total depopulation cross sections of Rb(ns) and Rb(nd) levels by collisions with ${\mathrm{NH}}_3$ have been measured over a wide range of n values (24≤n≤49). The analysis of the n-dependent behavior of the cross sections reveals that ${\mathrm{NH}}_3$ inversion can produce a very efficient l-mixing process via a quasiresonant mechanism. This behavior appears qualitatively well described by theoretical calculations based on the impulse approximation (IA). A quantitative comparison between theory and experiment appears difficult, but it seems that the IA should provide reasonable estimates (within a factor of 4), though its use for large dipole moment (1.47 D for ${\mathrm{NH}}_3$) is questionable from a theoretical point of view.