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Title: X-ray emission cross sections following charge exchange by multiply charged ions of astrophysical interest

Abstract

State selective nl-electron capture cross sections are presented for highly charged ions with Z=6-10 colliding with atoms and molecules. The energy range investigated was from 1 eV/amu(v=0.006 a.u.)to 100 keV/amu(v=2.0 a.u.). The energy dependence of the l-level populations is investigated. The K shell x-ray emission cross sections are determined by using the calculated state-selective electron capture results as input and then applying hydrogenic branching and cascading values for the photon emission. A major shift in the line emission from being almost solely Lyman-{alpha} transitions at the highest collisions energies to strong high-n to 1s transitions at the lowest energies is observed. The calculated cross sections are in reasonable accord with measurements made by Greenwood et al. [Phys. Rev. A 63, 062707 (2001)], using O{sup 8+} and Ne{sup 10+} on various targets at 3 keV/amu. The calculations are also in accord with x-ray emission cross section data obtained on the EBIT machine at Lawrence Livermore National Laboratory (LLNL) where O{sup 8+} and Ne{sup 10+} high resolution measurements were made at a temperature of 10 eV/amu for a series of targets with varying ionization potentials. The Ne{sup 10+} data clearly shows the contribution from multiple capture followed by Auger autoionization in themore » line emission spectra. Our calculated line emission cross sections are used to provide an ab initio determination of the soft x-ray spectrum of comet C/Linear 1999 S4 that was observed on the Chandra X-ray Observatory. The calculations show that the spectrum is due to the charge exchange of the neutral gases in the comet's coma with the ions of the slow solar wind.« less

Authors:
;  [1];  [2]
  1. Physics Department, University of Missouri-Rolla, Rolla Missouri 65401 (United States)
  2. Department of Physics, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
Publication Date:
OSTI Identifier:
20974594
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevA.73.022723; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AUGER EFFECT; CHARGE EXCHANGE; COMETS; CROSS SECTIONS; ELECTRON CAPTURE; EMISSION SPECTRA; ENERGY DEPENDENCE; ION-ATOM COLLISIONS; ION-MOLECULE COLLISIONS; IONIZATION POTENTIAL; K SHELL; MULTICHARGED IONS; NEON IONS; OXYGEN IONS; PHOTON EMISSION; SOFT X RADIATION; SOLAR WIND; SPECTRAL SHIFT; X-RAY SPECTRA

Citation Formats

Otranto, S., Olson, R. E., and Beiersdorfer, P.. X-ray emission cross sections following charge exchange by multiply charged ions of astrophysical interest. United States: N. p., 2006. Web. doi:10.1103/PHYSREVA.73.022723.
Otranto, S., Olson, R. E., & Beiersdorfer, P.. X-ray emission cross sections following charge exchange by multiply charged ions of astrophysical interest. United States. doi:10.1103/PHYSREVA.73.022723.
Otranto, S., Olson, R. E., and Beiersdorfer, P.. Wed . "X-ray emission cross sections following charge exchange by multiply charged ions of astrophysical interest". United States. doi:10.1103/PHYSREVA.73.022723.
@article{osti_20974594,
title = {X-ray emission cross sections following charge exchange by multiply charged ions of astrophysical interest},
author = {Otranto, S. and Olson, R. E. and Beiersdorfer, P.},
abstractNote = {State selective nl-electron capture cross sections are presented for highly charged ions with Z=6-10 colliding with atoms and molecules. The energy range investigated was from 1 eV/amu(v=0.006 a.u.)to 100 keV/amu(v=2.0 a.u.). The energy dependence of the l-level populations is investigated. The K shell x-ray emission cross sections are determined by using the calculated state-selective electron capture results as input and then applying hydrogenic branching and cascading values for the photon emission. A major shift in the line emission from being almost solely Lyman-{alpha} transitions at the highest collisions energies to strong high-n to 1s transitions at the lowest energies is observed. The calculated cross sections are in reasonable accord with measurements made by Greenwood et al. [Phys. Rev. A 63, 062707 (2001)], using O{sup 8+} and Ne{sup 10+} on various targets at 3 keV/amu. The calculations are also in accord with x-ray emission cross section data obtained on the EBIT machine at Lawrence Livermore National Laboratory (LLNL) where O{sup 8+} and Ne{sup 10+} high resolution measurements were made at a temperature of 10 eV/amu for a series of targets with varying ionization potentials. The Ne{sup 10+} data clearly shows the contribution from multiple capture followed by Auger autoionization in the line emission spectra. Our calculated line emission cross sections are used to provide an ab initio determination of the soft x-ray spectrum of comet C/Linear 1999 S4 that was observed on the Chandra X-ray Observatory. The calculations show that the spectrum is due to the charge exchange of the neutral gases in the comet's coma with the ions of the slow solar wind.},
doi = {10.1103/PHYSREVA.73.022723},
journal = {Physical Review. A},
number = 2,
volume = 73,
place = {United States},
year = {Wed Feb 15 00:00:00 EST 2006},
month = {Wed Feb 15 00:00:00 EST 2006}
}