Collisional excitation of Na-Rydberg atoms

I. I. Ryabtsev, Denis B. Tretyakov, Ilya I. Beterov +3 more

Collisional and thermal ionization of sodium n S and n D Rydberg atoms with n = 8–20 has been studied. The experiments were performed using a two-step pulsed laser excitation in an effusive atomic beam at atom density of about 2 × 10 10 cm −3 . Molecular and atomic ions from associative, Penning and thermal ionization processes were detected. It was found that the atomic ions were created mainly due to photoionization of Rydberg atoms by photons of blackbody radiation at the ambient temperature of 300 K. Blackbody ionization rates and effective lifetimes of Rydberg states of interest were determined. The molecular ions were found to be from associative ionization in Na( nL ) + Na(3S) collisions. Rate constants of associative ionization have been measured using an original method based on relative measurements of Na + 2 and Na + ion signals.

James Veale

V. M. Borodin, I. I. Fabrikant, Andrey K. Kazansky

I. I. Ryabtsev, Ilya I. Beterov, Denis B. Tretyakov +4 more

The results of the experimental and theoretical study on associative ionization of laser excited Na Rydberg atoms in collisions with ground-state atoms and on thermal ionization by blackbody radiation in single and crossed effusive atomic beams are reported and discussed.

F. B. Dunning, R. F. Stebbings

Thomas F. Gallagher, S. A. Edelstein, R. M. Hill

Collisions with rare-gas atoms are observed to produce a lengthening of the lifetime of the highly excited ($n=5\ensuremath{-}10$) $d$ states of Na. The effect is interpreted as collisional angular momentum mixing of the $d$ state with $l>2$ states; thus the average lifetime of all states for which $l>~2$ is observed. The cross section for the process appears to increase as the geometrical cross section of the excited atom.