Core dictionary (coreCIF) version 2.4.5
Polarization ratio of the diffraction beam incident on the crystal. It is the ratio of the perpendicularly polarized to the parallel polarized components of the radiation. The perpendicular component forms an angle of _diffrn_radiation_polarisn_norm to the normal to the diffraction plane of the sample (i.e. the plane containing the incident and reflected beams).
The permitted range is 0.0 -> infinity