Nonstatistical enhancement of the 1s2s2p {sup 4}P state in electron transfer in 0.5-1.0-MeV/u C{sup 4,5+} + He and Ne collisions

Journal Article · Fri Feb 15 04:00:00 EST 2008 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.77.022706· OSTI ID:21140489

Strohschein, D; Baran, J; Tanis, J A ^[1]; Roehrbein, D; Kirchner, T ^[2]; Fritzsche, S ^[3]

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1. Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008 (United States)
2. Institut fuer Theoretische Physik, Technische Universitaet Clausthal, D-38768 Clausthal-Zellerfeld (Germany)
3. Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany)

Nonstatistical enhancements for formation of the metastable 1s2s2p {sup 4}P state compared to the similarly configured 1s2s2p {sup 2}P{sub -} and 1s2s2p {sup 2}P{sub +} states are observed following single electron transfer to C{sup 4+}(1s2s {sup 3}S) and double electron transfer to C{sup 5+}(1s) ions, respectively. Previously, similar enhancements were observed in the population of the {sup 4}P metastable state resulting from electron transfer in {approx}1 MeV/u F{sup 7,8+}+He and Ne collisions [J. A. Tanis et al., Phys. Rev. Lett. 92, 133201 (2004)]. The enhancements were attributed to a dynamical Pauli exchange mechanism involving projectile and target electrons having the same spin alignment. Recently, it was suggested that the enhancement might be due to cascade effects following electron transfer to states with n>3. To further understand the observed enhancement of the {sup 4}P state, new investigations of Auger emission spectra in collisions of 0.5-1 MeV/u C{sup 4,5+} with He and Ne targets have been conducted. Experimental ratios of the resulting {sup 4}P intensities to the sum of the {sup 2}P{sub -} and {sup 2}P{sub +} intensities for the collision systems studied give values three to four times larger than expected based solely on spin statistics for single transfer to C{sup 4+}(1s2s {sup 3}S) and double transfer to C{sup 5+}(1s). Theoretical calculations suggest that about half of the observed enhancement is caused by cascade effects.

• OSTI ID: 21140489
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 77; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
AUGER ELECTRON SPECTROSCOPY
CARBON
CARBON IONS
CHARGE EXCHANGE
ELECTRON TRANSFER
ELECTRONS
HELIUM
ION-ATOM COLLISIONS
METASTABLE STATES
MEV RANGE
MULTICHARGED IONS
NEON
SPIN
STATISTICS