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Title: Finite-temperature random-phase approximation for spectroscopic properties of neon plasmas

Abstract

A finite-temperature random-phase approximation (FTRPA) is applied to calculate oscillator strengths for excitations in hot and dense plasmas. Application of the FTRPA provides a convenient, self-consistent method with which to explore coupled-channel effects of excited electrons in a dense plasma. We present FTRPA calculations that include coupled-channel effects. The inclusion of these effects is shown to cause significant differences in the oscillator strength for a prototypical case of {sup 1}P excitation in neon when compared with single-channel and with average-atom calculations. Trends as a function of temperature and density are also discussed.

Authors:
;  [1];  [2];  [1];  [3]
  1. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
  2. Applied Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
20982200
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevA.75.024701; (c) 2007 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; ATOMS; COUPLED CHANNEL THEORY; DENSITY; ELECTRON TEMPERATURE; ELECTRONS; EXCITATION; EXCITED STATES; ION TEMPERATURE; NEON; OSCILLATOR STRENGTHS; PLASMA; PLASMA DENSITY; RANDOM PHASE APPROXIMATION; TEMPERATURE DEPENDENCE

Citation Formats

Colgan, J., Collins, L. A., Fontes, C. J., Csanak, G., and Department of Physics, University of Nevada, Reno, Nevada 89557. Finite-temperature random-phase approximation for spectroscopic properties of neon plasmas. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.024701.
Colgan, J., Collins, L. A., Fontes, C. J., Csanak, G., & Department of Physics, University of Nevada, Reno, Nevada 89557. Finite-temperature random-phase approximation for spectroscopic properties of neon plasmas. United States. doi:10.1103/PHYSREVA.75.024701.
Colgan, J., Collins, L. A., Fontes, C. J., Csanak, G., and Department of Physics, University of Nevada, Reno, Nevada 89557. Thu . "Finite-temperature random-phase approximation for spectroscopic properties of neon plasmas". United States. doi:10.1103/PHYSREVA.75.024701.
@article{osti_20982200,
title = {Finite-temperature random-phase approximation for spectroscopic properties of neon plasmas},
author = {Colgan, J. and Collins, L. A. and Fontes, C. J. and Csanak, G. and Department of Physics, University of Nevada, Reno, Nevada 89557},
abstractNote = {A finite-temperature random-phase approximation (FTRPA) is applied to calculate oscillator strengths for excitations in hot and dense plasmas. Application of the FTRPA provides a convenient, self-consistent method with which to explore coupled-channel effects of excited electrons in a dense plasma. We present FTRPA calculations that include coupled-channel effects. The inclusion of these effects is shown to cause significant differences in the oscillator strength for a prototypical case of {sup 1}P excitation in neon when compared with single-channel and with average-atom calculations. Trends as a function of temperature and density are also discussed.},
doi = {10.1103/PHYSREVA.75.024701},
journal = {Physical Review. A},
number = 2,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
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  • The modified finite-temperature random phase approximation (FT-RPA) has been constructed by taking the influence of thermostat on the structure of quasiparticles into account. The modified FT-RPA linear response for electric quadrupole ({lambda}{sup {pi}}=2{sup +}) and octupole ({lambda}{sup {pi}}=3{sup {minus}}) excitations in {sup 58}Ni has been calculated as a function of the nuclear temperature. As compared to the conventional FT-RPA, the modified FT-RPA has given a stronger spreading for the strength distribution of quadrupole excitations at finite temperature {ital T}{le}3 MeV.
  • The nuclear collective response at finite temperature is investigated for the first time in the quantum framework of the small amplitude limit of the extended time-dependent Hartree-Fock approach, including a non-Markovian collision term. It is shown that the collision width satisfies a secular equation. By employing a Skyrme force, the isoscalar monopole, isovector dipole, and isoscalar quadrupole excitations in {sup 40}Ca are calculated and important quantum features are pointed out. The collisional damping due to decay into incoherent two-particle{endash}two-hole states is small at low temperatures but increases rapidly at higher temperatures. {copyright} {ital 1998} {ital The American Physical Society}
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