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Phys. Rev. A 66, 062710 (2002) [10 pages]

Photoionization of Ne+ using synchrotron radiation

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A. M. Covington, A. Aguilar, I. R. Covington, M. F. Gharaibeh, G. Hinojosa*, C. A. Shirley, and R. A. Phaneuf
Department of Physics, MS 220, University of Nevada, Reno, Nevada 89557-0058

I. Álvarez and C. Cisneros
Centro de Ciencias Físicas, Universidad National Autónoma de México, Apartado Postal 6-96, Cuernavaca 62131, Mexico

I. Dominguez-Lopez, M. M. Sant’Anna, and A. S. Schlachter
Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 7-100, Berkeley, California 94720

B. M. McLaughlin§ and A. Dalgarno
Institute for Theoretical Atomic and Molecular Physics, Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138

Received 10 September 2002; published 30 December 2002

Absolute measurements of cross sections for photoionization of a statistical admixture of Ne+ in the 2P3/2o ground state and the 2P1/2o metastable state are reported in the energy range 40–71 eV at photon energy resolutions ranging from 22 meV to 2 meV. The experiments were performed using synchrotron radiation from an undulator beamline of the Advanced Light Source with a newly developed ion-photon-beam endstation. The data are characterized by multiple Rydberg series of autoionizing resonances superimposed upon a direct photoionization background cross section where some of the observed resonance line shapes show evidence of interference between the direct and indirect photoionization channels. The resonance features are assigned spectroscopically, and their energies and quantum defects are tabulated. The experimental photoionization cross sections are in satisfactory agreement with the predictions from theoretical calculations performed in intermediate coupling using the semirelativistic Breit-Pauli approximation with ten states. The resonances nearest to the ionization thresholds exhibit anomalous behavior with respect to their positions and strengths due to the presence of interloping resonances associated with higher-lying ionic states causing disruption of the regular Rydberg spectral pattern.

© 2002 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevA.66.062710
DOI:
10.1103/PhysRevA.66.062710
PACS:
32.80.Dz

*Present address: Centro de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 6-96, Cuernavaca 62131, Mexico.

Present address: Centro Nacional de Metrología, Querétaro, Qro. 76900, Mexico.

Present address: Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21945-970 Rio de Janeiro, RJ, Brazil.

§Present address: Department of Applied Mathematics and Theoretical Physics, The Queens University of Belfast, Belfast BT7 1NN, United Kingdom.