Stark broadening of Sr I spectral lines

Astronomy and Astrophysics Supplement Series, Jul 2018

Using a semiclassical approach, we have calculated electron-, proton-, and ionized helium-impact line widths and shifts for 33 Sr I multiplets for perturber densities 1013 cm-3 (for stellar plasma research) and 1015- 1018 cm-3 (for laboratory plasma research) and temperatures T = 2 500 - 50 000 K.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://aas.aanda.org/articles/aas/pdf/1996/15/ds1192.pdf

Stark broadening of Sr I spectral lines

Astron. Astrophys. Suppl. Ser. Stark broadening of Sr I spectral lines? M.S. Dimitrijevic 1 S. Sahal-Brechot 0 0 Laboratoire \Astrophysique, Atomes et Molecules", Departement Atomes et Molecules en Astrophysique, Unite associee au C.N.R.S. No. 812, Observatoire de Paris-Meudon , 92190 Meudon , France 1 Astronomical Observatory , Volgina 7, 11050 Belgrade , Yugoslavia | Using a semiclassical approach, we have calculated electron−, proton−, and ionized helium−impact line widths and shifts for 33 Sr I multiplets for perturber densities 1013 cm−3 (for stellar plasma research) and 10151018 cm−3 (for laboratory plasma research) and temperatures T = 2 500 − 50 000 K. lines; pro le-atomic data 1. Introduction Strontium lines are present in solar and stellar spectra. E.g. Komarov & Basak (1993) have found neutral strontium lines in the spectra of Sun and two Praesepe's stars. They are also of interest since Sr is one of thermonuclear s - processes product in stars and its overabundance is observed in CH and metal de cient barium stars (Sleivyte & Bartkevicius 1995) . Neutral strontium lines are also of interest for the investigation of laboratory plasmas. Consequently, Kato et al. (1984) investigated wavelength shifts of Sr I lines emitted by an inductively coupled plasma and Karabut et al. (1980) dynamics of strontium line shapes during a pulsed discharge. Such lines have been considered theoretically as well by Davis (1972) , for research of a laser - generated barium plasma. In order to continue our research of Stark broadening parameters needed for the investigation of astrophysical and laboratory plasmas and to provide the needed Stark broadening data, we have calculated within the semiclassical-perturbation formalism (Sahal−Brechot 1969a,b) electron-, proton-, and ionized helium-impact line widths and shifts for 33 Sr I multiplets. A summary of the formalism is given in Dimitrijevic & Sahal-Brechot (1984). 2. Results and discussion Energy levels for Sr I lines have been taken from Moore (1971) . Oscillator strengths have been calculated by using Send o print requests to: M.S. Dimitrijevic ?Table 1 is only available in electronic form: The material published electronically can be accessed: by ftp at cdsarc.ustrasbg.fr or 130.79.128.5 or on WWW at: http//cdsweb.ustrasbg.fr/abstract.html the method of Bates & Damgaard (1949) and the tables of Oertel & Shomo (1968) . For higher levels, the method described by Van Regemorter et al. (1979 ) has been used. We note that Gruzdev (1967) has found that the semiempirical and Hartree - Fock calculations of Sr I oscillator strengths agree fairly well with the f values calculated by the method of Coulomb approximation. In addition to electron-impact full halfwidths and shifts, Stark-broadening parameters due to proton-, and He II- impacts have been calculated. Our results for 33 Sr I multiplets are shown in Table 1 (accesible only in electronic form), for perturber densities 1013 cm−3 (for stellar plasma research) and 1015− 1018 cm−3 (for laboratory plasma research) and temperatures T = 2 500 − 50 000 K. We also specify a parameter c (Dimitrijevic & Sahal−Brechot 1984) , which gives an estimate for the maximum perturber density for which the line may be treated as isolated when it is divided by the corresponding full width at half maximum. For each value given in Table 1, the collision volume (V ) multiplied by the perturber density (N ) is much less than one and the impact approximation is valid (Sahal−Brechot 1969a,b) . Values for N V > 0.5 are not given and values for 0.1 < N V 0.5 are denoted by an asterisk. When the impact approximation is not valid, the ion broadening contribution may be estimated by using quasistatic approach (Sahal−Brechot 1991; Griem 1974) . In the region between where neither of these two approximations is valid, a uni ed type theory should be used. For example in Barnard et al. (1974) , a simple analytical formulas for such a case are given. The accuracy of the results obtained decreases when broadening by ion interactions becomes important. M.S. Dimitrijevic and S. Sahal-Brechot: Stark broadening of Sr I spectral lines Acknowledgements. This work is a part of the project \Physics and dynamics of celestial bodies", supported by Ministry of Science and Technology of Serbia. Barnard A.J. , Cooper J. , Smith E.W. , 1974 , JQSRT 14 , 1025 Bates D.R. , Damgaard A. , 1949 , Trans. Roy. Soc. London Ser. A 242 , 101 Davis J. , 1972 , JQSRT 12 , 1351 Dimitrijevic M.S. , Sahal−Brechot S. , 1984 , JQSRT 31 , 301 Griem H.R. , 1974 , Spectral Line Broadening by Plasmas. Academic Press, New York Gruzdev P.F. , 1967 , Opt. Spektrosk. 22 , 169 Karabut E.K. , Kravchenko V.F. , Mikhalevskii V.S. , 1980 , Opt. Spectrosc. 48 , 386 Kato K. , Fukushima H. , Nakajima T. , 1984 , Spectrochim. Acta B 39 , 979 Komarov N.S. , Basak N. Yu ., 1993 , Astron. Zh. 70 , 111 Moore C.E. , 1971 , Atomic Energy Levels II , NSRDS-NBS 35, Washin (...truncated)


This is a preview of a remote PDF: https://aas.aanda.org/articles/aas/pdf/1996/15/ds1192.pdf

M. S. Dimitrijević, S. Sahal-Bréchot. Stark broadening of Sr I spectral lines, Astronomy and Astrophysics Supplement Series, pp. 529-530, Volume 119, Issue 3, DOI: 10.1051/aas:1996265