  Using a quantum electrodynamical approach, we derive the scattering phase
matrices for polarized radiation involving forbidden line transitions and in
the presence of an external magnetic field. The case of (J=0->2->0) scattering
is considered as an example. The non-magnetic Rayleigh scattering phase matrix
is also presented. The Stokes profiles in a single scattering event are
computed for the strong field (Zeeman) and weak field (Hanle) limits, covering
also the regime of intermediate field strengths (Hanle- Zeeman).
