Intensity (left panel) and Stokes Q/I (right panel) profiles as a function of wavelength in the spectral ranges centered on the K I D₂ line. The RT calculations were carried out in the absence of a magnetic field and for a two-term atomic model with HFS. The results of the calculation accounting for PRD (black curves) are compared to those obtained in the complete frequency redistribution (CRD) limit (red curves) as described in the text. In this figure and all those shown below, the calculations were carried out considering the FAL-C atmospheric model.