Polarized Partial Frequency Redistribution in Subordinate Lines. I. Resonance Scattering with Collisions

Abstract

Using a previously established theory, we derive a suitable form of the laboratory frame redistribution matrix for the resonance scattering in subordinate lines, allowing for the radiative as well as collisional broadening of both atomic levels involved. The lower level, though broadened, is assumed to be unpolarized. The elastic collisions both in the upper and lower levels are taken into account. We show that, in situations, when elastic collisions in the lower level can be neglected, the redistribution matrix for subordinate lines takes a form that is analogous to the corresponding case of resonance lines. Further, in the case of no-lower-level interactions (i.e., infinitely sharp lower level), we recover the redistribution matrix for resonance lines. We express the redistribution matrix for subordinate lines in terms of the irreducible spherical tensors for polarimetry. For practical applications in one-dimensional polarized radiative transfer problem, we derive the azimuth averaged subordinate line redistribution matrix.