Abstract

In a cold collision between a ground- and an excited-state atom, a key issue is the survival of the atomic excitation during the course of the collision. For small detunings from resonance, the excitation is created at long range (e.g., >100 nm). Once excited, the atom pair begins to accelerate on the attractive R^-3 potential. For an inelastic- trap-loss collision to occur, the excited atom pair must reach short range (e.g., <5 nm). In the journey from long range to short range, there is a high probability that the excitation will decay, effectively turning off the collision. As the initial collision velocity is reduced, the collision time is lengthened and the probability for decay is enhanced. It is therefore predicted' ⁴ that the collision rate is suppressed as the temperature is lowered. A key aspect of this prediction is localization of the initial excitation, as occurs in a Landau-Zenei curve-crossing process.

© 1995 Optical Society of America