The absolute cross section for removal of Rydberg electrons from Na Rydberg atoms by impact of singly charged ions was measured. Ne+, Ar+, and Xe+, accelerated to energies 15 keV, bombarded a Na atomic-beam target that was laser excited to nd states, n=3045. Electron loss, the sum of ionization and charge transfer, was detected by collecting impact-produced Na+ from the target after 13 s exposure to the projectile beam. The velocity dependence of the cross section was measured for n=40 with projectile velocities v=0.83.7 times the Bohr orbital velocity of the target atoms. The n dependence was measured at reduced velocity v=2.0 for n=3045. 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 4.080.07 between n=1 and 45 was found. The results may be compared with H++H(1s) collisions at projectile energies 16340 keV.
|Number of pages||8|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|State||Published - 1986|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics