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Gigantic enhancement of atomic nondipole effects: The 3s{yields}3d resonance in Ca

Journal Article · · Physical Review. A
;  [1];  [2]
  1. Department of Physics and Earth Science, University of North Alabama, Florence, Alabama 35632 (United States)
  2. Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303 (United States)
Dramatic examples of the importance of nondipole effects in photoelectron angular distributions at photon energies as low as a few tens of eV are found. This occurs in 3p photoionization of the Ca(4s{sup 2}) atom and its ions Ca{sup +}(4s{sup 1}) and Ca{sup 2+}(4s{sup 0}) at photon energies corresponding to a quadrupole 3s{yields}3d resonance. The nondipole parameters are found to drastically increase to as much as 65% of the dipole counterpart. The quintessence is that this resonance turns out to be giant because of selective orbital collapse for the quadrupally excited 3d orbital. In addition, nondipole effects are known to result in an electric current--the drag current--in a gaseous medium upon photoionization of its atoms. We present our calculated data for the drag current in Ca vapor as well, in an attempt to trigger experimental studies of this interesting phenomenon in general. Calculations were performed within the framework of the random-phase approximation with exchange.
OSTI ID:
20718138
Journal Information:
Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 72; ISSN 1050-2947; ISSN PLRAAN
Country of Publication:
United States
Language:
English