COLLISIONAL DEPOPULATION OF EXCITED NA S-STATES BY HE, AR, AND XE

The authors have measured the collisional depopulation cross sections of Na s states from n=6 to 11. The maximum cross sections observed for He, Ar, and Xe, respectively, are ∼20, 20, and 100 2. The cross sections rise from ∼0.1 2 at n∼6 to a plateau at n∼10. The small size of the cross sections suggests that the process proceeds via the interaction of the Na+ core with the rare-gas atom. Specifically, this short-range interaction produces a transient dipole on the rare-gas atom which efficiently couples Na states of different n. This is an entirely different mechanism than that responsible for the collisional l mixing previously reported. © 1979 The American Physical Society.