The scattering effects of the redistribution function RIII(x′, n′; x, n) on spectral line formation

The effects of frequency and angular redistribution on line formation are examined in static isothermal atmospheres for scattering described by the redistribution function R_III(x′, n′; x, n). For an optically thin atmosphere, it is found that the emergent line intensities obtained using R_III are essentially the same as R_I and R_II. In the case of a semi-infinite atmosphere, the emergent line intensities obtained using R_III, whether angle-averaged or angle-dependent, did not differ substantially from the complete redistribution results.