Recent experiments on near-threshold electron-impact excitation of multiply charged ions

Journal Article · Tue Sep 01 04:00:00 EDT 1998 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.56562· OSTI ID:678849

Bannister, M E ^[1]; Djuric, N; Woitke, O; Dunn, G H ^[2]; Chung, Y ^[3]; Smith, A C ^[4]; Wallbank, B ^[5]

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1. Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6372 (United States)
2. JILA, University of Colorado and National Institute of Standards and Technology, Boulder, Colorado 80309-0440 (United States)
3. Department of Physics, Chungnam National University, Gung-Dong 220, 3005-764 Daejon, South (Korea)
4. Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)
5. Department of Physics, St. Francis Xavier University, Antigonish, Nova Scotia, Canada, B2G 2W5 (CANADA)

Some recent measurements of excitation of multiply charged ions by electrons studied in beam-beam experiments are highlighted. The emphasis is on absolute total cross sections measured with the merged electron-ion beams energy-loss (MEIBEL) technique, although some results obtained with the crossed-beams fluorescence method are also presented. The MEIBEL technique allows the investigation of optically-allowed and forbidden transitions with sufficient energy resolution, typically about 0.2 eV, to resolve resonance structures in the cross sections. Results from the JILA/ORNL MEIBEL experiment on dipole-allowed transitions in several ions demonstrate the success of various theoretical methods in predicting cross sections in the absence of resonances. Comparisons of R-matrix calculations and measured cross sections for spin-forbidden transitions in Mg-like Si{sup 2+} and Ar{sup 6+}, however, show that further refinements to the theory are needed in order to more accurately predict cross sections involving significant contributions from dielectronic resonances and interactions between neighboring resonances. {copyright} {ital 1998 American Institute of Physics.}

• Sponsoring Organization: USDOE
• DOE Contract Number: AI05-86ER53237; AC05-96OR22464
• OSTI ID: 678849
• Report Number(s): CONF-980365--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 443; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ELECTRON-ION COLLISIONS
ENERGY-LOSS SPECTROSCOPY
EXCITATION
FLUORESCENCE SPECTROSCOPY
FORBIDDEN TRANSITIONS
IONS
MULTICHARGED IONS
THRESHOLD ENERGY
TOTAL CROSS SECTIONS