EDP Sciences
Free access
Issue
A&A
Volume 426, Number 2, November I 2004
Page(s) 707 - 715
Section Atomic, molecular and nuclear data
DOI http://dx.doi.org/10.1051/0004-6361:20047188


A&A 426, 707-715 (2004)
DOI: 10.1051/0004-6361:20047188

Collisional depolarization and transfer rates of spectral lines by atomic hydrogen

IV. Application to ionised atoms
M. Derouich1, S. Sahal-Bréchot1, 2 and P. S. Barklem2

1  Observatoire de Paris-Meudon, LERMA UMR CNRS 8112, 5, Place Jules Janssen, 92195 Meudon Cedex, France
2  Observatoire de Paris-Meudon, LERMA UMR CNRS 8112, 5, Place Jules Janssen, 92195 Meudon Cedex, France Department of Astronomy and Space Physics, Uppsala University, Box 515, 75120 Uppsala, Sweden
    e-mail: Moncef.Derouich@obspm.fr

(Received 9 February 2004 / Accepted 29 June 2004)

Abstract
The semi-classical theory of collisional depolarization of spectral lines that we have applied to neutral atoms in previous papers is extended to spectral lines of singly ionised atoms. In order to validate our general theory, we compare our results to quantum chemistry calculations obtained for the particular cases of the $\rm 3d$ $\rm ^2D$ and $\rm 4p$  $\rm ^2P$ states of the CaII ion. As a demonstration of the universality of our theory and the easiness of its application, we calculate depolarization and polarization transfer rates for the $\rm 5p$ $\rm ^2P$ state of the SrII ion. Analytical expressions of all rates as a function of local temperature are given. Our results for the CaII ion are compared to recent quantum chemistry calculations. A discussion of our results is presented.


Key words: Sun: atmosphere -- atomic processes -- line: formation -- polarization




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