Electron capture from aligned p-state Rydberg atoms

Journal Article · Wed Oct 01 04:00:00 EDT 2003 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.68.042709· OSTI ID:20640335

Hwang, C S; MacAdam, K B ^[1]

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1. Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States)

Electron capture by Li{sup +} ions from aligned Na(25p) Rydberg atoms was measured as a function of the approach angle between the alignment axis of the target-atom wave functions and the ion-beam direction, over a range of reduced velocity v-tilde=1.0-2.0, where v-tilde=v{sub ion}/v{sub e}. A Stark barrel was used to generate uniform rotatable electric fields over the collision volume and to align Rydberg atoms along the field at arbitrary angles over a full range of 360 deg. A mixture of Na(25p) fine-structure levels was prepared in the Stark barrel by two-step pulsed laser excitation in the presence of a moderate electric field (about 56 V/cm) followed by adiabatic switching and rotation to 1.8 V/cm. The relative capture cross section, which varied sinusoidally as a function of the alignment angle, had maxima at 0 deg. and 180 deg. and minima at 90 deg. and 270 deg. throughout this velocity range, showing a strong preference for capture from the endwise arrangement. The alignment effect weakened as the projectile velocity was increased. The Rydberg-state results differ in both magnitude and trend from those based on low-lying aligned states. The spin-independent asymmetry parameter was inferred from the angle-dependent capture cross sections after the spin-orbit depolarization effect in the mixed Rydberg p state was fully accounted for so that the results correspond purely to molecular {sigma} and {pi} collision geometries.

• OSTI ID: 20640335
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 68; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ALIGNMENT
ASYMMETRY
ATOMS
CROSS SECTIONS
DEPOLARIZATION
ELECTRIC FIELDS
ELECTRON CAPTURE
EXCITATION
FINE STRUCTURE
GEOMETRY
ION BEAMS
LASER RADIATION
LITHIUM IONS
MIXTURES
P STATES
PHOTON-ATOM COLLISIONS
ROTATION
RYDBERG STATES
SPIN
STARK EFFECT
VELOCITY
WAVE FUNCTIONS