Variation of Electron Capture From a Na Stark State as a Function of Alignment Angle.
Abstract
Electron capture from n=24 sodium Rydberg Stark-state targets by singly charged ions has been studied from reduced velocity tilde v = 0.3 to 0.5 as the angle between electron-cloud polarization and the incident beam direction is varied from 0^circ to 360^circ. The Stark state was prepared by two-step laser excitation via 3p_3/2 to the top manifold state of n = 24 at F = 200 V/cm (the ``Stark field'') oriented along the ion-beam axis. F was then reduced electronically to 1.34 V/cm (the ``barrel field''). The barrel field was oriented at angle α (180^circ corresponds to a field directed opposite the incident ion beam and yields an electronic wavefunction extending ``upstream.'') The field vector changed smoothly in about 1 μs so that the top manifold state followed adiabatically to low field, yielding atoms with arbitrary alignment angle. Resulting capture cross sections (CCS) are symmetric about a maximum at 180^circ and fall off toward 0^circ and 360^circ. At lower tilde v the (upstream/downstream) ratio grows, and two shoulders appear at 90^circ and 270^circ. These results show good agreement with classically calculated CCSs. One-, three- and five-swap capture dominates the total CCS at different angles α.
- Publication:
-
APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts
- Pub Date:
- May 1996
- Bibcode:
- 1996APS..DMP..WP40M