The effect of three types of frequency domains on Q/I and U/I profiles computed using angle-dependent PRD functions. Solid lines correspond to the 1D cut-off assumption (x_c = 3), dotted lines to 2D square domains (), and dashed lines to the approximation-II of Bommier (1997b). The model parameters are the same as in Fig. 2a. Panel a) corresponds to single scattered solutions, and panel b) to the multiple scattered solutions.