Frequency Redistribution Function for the Polarized Two-Term Atom
  We present a generalized frequency redistribution function for the polarized two-term atom in an arbitrary magnetic field. This result is derived within a new formulation of the quantum problem of coherent scattering of polarized radiation by atoms in the collisionless regime. The general theory, which is based on a diagrammatic treatment of the atom-photon interaction, is still work in progress. However, the results anticipated here are relevant enough for the study of the magnetism of the solar chromosphere and of interest for astrophysics in general. 
R. Casini, M. Landi Degl'Innocenti, R. Manso Sainz, E. Landi   Degl'Innocenti, M. Landolfi
astro-ph.SR