Collisional depolarization and transfer rates of spectral lines by atomic hydrogen . IV : application to ionised atoms

The semi-classical theory of collisional depolarization of spectral lines of neutral atoms by atomic hydrogen (Derouich et al. 2003a; Derouich et al. 2003b; Derouich et al. 2004 and references therein) is extended to spectral lines of singly ionised atoms. In this paper we apply our general method to the particular cases of the 3d D and 4p P states of the CaII ion and to the 5p P 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.