A merged-beams energy-loss technique for electron-ion excitation: Absolute total cross sections for o5+ (2s>2p)

Published

October 16, 2008

Author(s)

E W. Bell, X Q. Guo, J L. Forand, K Rinn, D R. Swenson, J S. Thompson, G H. Dunn, M E. Bannister, D C. Gregory, Ray A. Phaneuf, A C. Smith, A Muller, C A. Timmer, E K. Wahlin, B D. DePaola, D S. Belic

Abstract

A merged-beams electron-energy-loss technique is described by which absolute cross sections can be measured for near-threshold electro-impact excitation of multiply charged ions. Results are reported here for absolute total electron-impact excitation cross sections for the P⁵⁺ (2s>2p) transition from below threshold to 1.6 eV above threshold. The experimental data are in good agreement with a seven state close-coupling calculation throughout the energy range of the experiment. Results agree with calculations showing more than 90 percent of the electrons causing excitation are ejected in the backward direction in the center-of-mass frame. This backscattering is shown in both quantum-mechanical and semi-classical calculations. Evidence is observed for high-lying metastable autoionizing states with a lifetime of approximately 0.9 υs which are made to ionize by electron impact.

Citation

Physical Review A (Atomic, Molecular and Optical Physics)

Pub Type

Journals

Keywords

electron-impact excitation, measurement techniques, merged beams, O⁵⁺

Citation

Bell, E. , Guo, X. , Forand, J. , Rinn, K. , Swenson, D. , Thompson, J. , Dunn, G. , Bannister, M. , Gregory, D. , Phaneuf, R. , Smith, A. , Muller, A. , Timmer, C. , Wahlin, E. , DePaola, B. and Belic, D. (2008), A merged-beams energy-loss technique for electron-ion excitation: Absolute total cross sections for o⁵⁺ (2s>2p), Physical Review A (Atomic, Molecular and Optical Physics) (Accessed April 25, 2024)