On the polarization of resonantly scattered emission lines - 1. Emission and absorption coefficients in an anisotropic radiation field

Source functions and absorptions coefficients for polarized radiation in a given ansiotropic radiation field are calculated for a variety of permitted electric dipole transitions in the L-S coupling limit. Collisional, radiative and magnetic mixing of the ground sublevels are all considered. The polarization of the self-consistent, emergent radiation field is computed, using an anisotropic escape probability formalism to treat the radiative transfer. It is found that the radiative mixing can enhance the polarization for transitions with large angular momentum, and degrees of polarization less than or approximately 10 per cent are obtained for transitions with small angular momentum.