Effect of Electron Capture on Spectral Line Broadening in Hot Dense Plasmas

T. A. Gomez, T. Nagayama, C. J. Fontes, D. P. Kilcrease, S. B. Hansen, M. C. Zammit, D. V. Fursa, A. S. Kadyrov, and I. Bray

Phys. Rev. Lett. 124, 055003 – Published 5 February 2020

Abstract

Accurate calculation of spectral line broadening is important for many hot, dense plasma applications. However, calculated line widths have significantly underestimated measured widths for $Δ n = 0$ lines of Li-like ions, which is known as the isolated-line problem. In this Letter, scrutinization of the line-width derivation reveals that the commonly used expression neglects a potentially important contribution from electron-capture. Line-width calculations including this process are performed with two independent codes, both of which removed the discrepancies at temperatures below 10 eV. The revised calculations also suggest the remaining discrepancy scales more strongly with electron temperature than the atomic number as was previously suggested.

Received 3 October 2019
Revised 10 December 2019
Accepted 24 December 2019

DOI:https://doi.org/10.1103/PhysRevLett.124.055003

Physics Subject Headings (PhySH)

Atomic spectra Electron & positron scattering Electronic excitation & ionization Electronic transitions High-energy-density plasmas Laboratory studies of space & astrophysical plasmas

Atomic, Molecular & OpticalPlasma Physics

Authors & Affiliations

T. A. Gomez ^1,*, T. Nagayama¹, C. J. Fontes ², D. P. Kilcrease², S. B. Hansen¹, M. C. Zammit², D. V. Fursa ³, A. S. Kadyrov ³, and I. Bray³

¹Sandia National Laboratories, Albuquerque, New Mexico 87123, USA
²Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
³Curtin Institute of Computation and Department of Physics and Astronomy, GPO Box U1987 Perth, Western Australia 6845, Australia