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Title: Updated single-electron-capture cross-section scaling rule for A{sup q+}+H{sub 2} collisions

Abstract

An updated high-energy universal scaling rule for single electron capture cross sections is presented for A{sup q+}+H{sub 2} collisions. The current scaling rule is built empirically on experimental data using a wide range of projectile ions and collision energies. The inclusion of such a broad range of values results in a model that more accurately predicts the single capture cross sections for a much wider range of collision systems. The current scaling rule is compared to three similar scaling rules to illustrate how using limited data to develop a universal scaling rule effects a models general predictive power. The effects of all four scaling rules on both experimental and theoretical data are examined.

Authors:
 [1]
  1. Ouachita Baptist University, 410 Ouachita Street, Arkadelphia, Arkansas 71998 (United States)
Publication Date:
OSTI Identifier:
20786916
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.73.032710; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; CROSS SECTIONS; ELECTRON CAPTURE; HYDROGEN; ION-MOLECULE COLLISIONS; IONS; MOLECULES

Citation Formats

Cornelius, Kevin R. Updated single-electron-capture cross-section scaling rule for A{sup q+}+H{sub 2} collisions. United States: N. p., 2006. Web. doi:10.1103/PHYSREVA.73.0.
Cornelius, Kevin R. Updated single-electron-capture cross-section scaling rule for A{sup q+}+H{sub 2} collisions. United States. doi:10.1103/PHYSREVA.73.0.
Cornelius, Kevin R. Wed . "Updated single-electron-capture cross-section scaling rule for A{sup q+}+H{sub 2} collisions". United States. doi:10.1103/PHYSREVA.73.0.
@article{osti_20786916,
title = {Updated single-electron-capture cross-section scaling rule for A{sup q+}+H{sub 2} collisions},
author = {Cornelius, Kevin R.},
abstractNote = {An updated high-energy universal scaling rule for single electron capture cross sections is presented for A{sup q+}+H{sub 2} collisions. The current scaling rule is built empirically on experimental data using a wide range of projectile ions and collision energies. The inclusion of such a broad range of values results in a model that more accurately predicts the single capture cross sections for a much wider range of collision systems. The current scaling rule is compared to three similar scaling rules to illustrate how using limited data to develop a universal scaling rule effects a models general predictive power. The effects of all four scaling rules on both experimental and theoretical data are examined.},
doi = {10.1103/PHYSREVA.73.0},
journal = {Physical Review. A},
number = 3,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • Recent experiments suggest that double-electron capture dominates, single-electron capture in He{sup 2+} + H{sub 2} collisions below 1 keV while single electron-capture becomes dominant above this energy. Another experiment suggests that double-electron capture is always the dominant process in Ar{sup q+} + H{sub 2} collisions in the energy region from 0.1 eV to a few keV. The authors theoretical results obtained by using a molecular orbital expansion method clearly confirm these experimental findings and provide a theoretical rationale based on adiabatic potentials and dynamic analysis.
  • An evaluation has been made of the existing experimental and theoretical cross-section data for electron capture and ionization in collisions of C/sup q//sup +/ and O/sup q//sup +/ ions (1less than or equal toqless than or equal toZ) with H, He, and H/sub 2/. Sets of recommended cross-section data with specified accuracies are presented in the energy range of interest to controlled thermonuclear fusion research. Chebyshev polynomial fits to the recommended data are also given. copyright 1988 Academic Press, Inc.
  • Partial cross sections for electron capture into specific n states are reported for 0.1- and 0.25-MeV/nucleon I/sup q//sup +/-H/sub 2/ collisions (q = 12--18). The measured cross sections show pronounced differences when compared to theoretical calculations based on a number of models for bare incident ions on atomic hydrogen.
  • Total electron-capture cross-section measurements are reported for C/sup q/+ (3< or =q< or =6) and O/sup q/+ (2< or =q< or =6) ions colliding with hydrogen atoms and molecules in the energy range (0.01< or =E< or =10) keV/amu. The cross sections range from (0.5--7) x 10/sup -15/ cm/sup 2/, and neither obey simple charge-scaling rules, nor exhibit uniform dependences on collision velocity in this energy range. For a given charge q, cross sections for the less-highly-stripped oxygen ions exceed those for carbon ions at energies below a few-hundred eV/amu. Comparison is made between these measurements and theoretical calculations whichmore » have heretofore remained untested at low collision energies. In general, the agreement is good for those systems where detailed perturbed-stationary-state theory is available, but is best with those calculations in which the collision dynamics as well as the molecular couplings are treated quantum mechanically. Generalized theories which work well for collision systems containing many bound electrons, do not give accurate representations of these few-electron systems at low energies.« less
  • The cross sections for single-electron capture, including transfer ionization, and for double-electron capture, have been measured for Ar{sup {ital q}+}+H{sub 2} for {ital q}=6, 7, 8, 9, and 11 with projectile energies from {ital q} eV to {ital q} keV. Theoretically, the cross sections for Ar{sup 6+} and Ar{sup 8+} impact were calculated using a molecular-orbital expansion method in the energy region from 240 eV to 80 keV, and are in good agreement with experiment. The single-electron-capture cross sections were found to be more than one order of magnitude larger than those for double capture in both experiment and theory.more » The single-electron-capture cross sections were also compared to the Langevin cross section, a scaling law developed by Mueller and Salzborn [Phys. Lett. 62A, 391 (1977)], and the absorbing sphere model.« less