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Electron loss from Na Rydberg atoms by ion impact

Journal Article · · Phys. Rev. A; (United States)

The absolute cross section for removal of Rydberg electrons from Na Rydberg atoms by impact of singly charged ions was measured. Ne/sup +/, Ar/sup +/, and Xe/sup +/, accelerated to energies 1--5 keV, bombarded a Na atomic-beam target that was laser excited to nd states, n = 30--45. Electron loss, the sum of ionization and charge transfer, was detected by collecting impact-produced Na/sup +/ from the target after 1--3 ..mu..s exposure to the projectile beam. The velocity dependence of the cross section was measured for n = 40 with projectile velocities v-italic-tilde = 0.8--3.7 times the Bohr orbital velocity of the target atoms. The n dependence was measured at reduced velocity v-italic-tilde = 2.0 for n = 30--45. A study of field ionization of higher collisionally excited states was made, and important corresponding corrections were applied to the data. The effects of collisional l change in the target and of l mixing due to applied, pulsed electric fields were noted. The absolute unnormalized cross section for n = 40 agreed with classical-trajectory calculations and with the classical binary-encounter approximation. The classically predicted n scaling of the cross section at fixed reduced velocity was directly demonstrated, and a scaling exponent 4.08 +- 0.07 between n = 1 and 45 was found. The results may be compared with H/sup +/+H(1s) collisions at projectile energies 16--340 keV.

Research Organization:
Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506
OSTI ID:
7104807
Journal Information:
Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 34:6; ISSN PLRAA
Country of Publication:
United States
Language:
English