A simple quadrature method for the evaluation of the redistribution functions RIII,IV(xÿ,nÿ;x,n).

A simple and fast technique for generating the angle-dependent redistribution functions R sub III (x', n'; x, n) and R sub IV (x', n'; x, n) is presented which uses a simple quadrature with an error-correction method that may be easily applied to many radiation-transport problems. It is noted that these functions describe photon redistribution when deviations from strict frequency coherency are present in an atom's frame. The R sub III function is shown to assume collisional broadening of the upper transition state resulting in complete redistribution in an atom's frame, while the R sub IV function assumes that both transition states are radiation broadened only and describes resonant scattering resulting in partial frequency coherence in an atom's frame. The functions are plotted against various parameters governing their behavior and are found to be strongly angle-dependent. The behavior of these angle-dependent functions is compared with that of their angle-averaged counterparts.