It has been found that the Pitts-Giovanelli formula gives a good account of diffuse reflectance over a large concentration range in model systems containing a soluble absorber in a dispersion of nonabsorbing particles. However, a very anisotropic scattering phase function is required. The concentration and wavelength dependence of the anisotropy factor are explored in the present work and are found to follow trends which are reminiscent of those predicted on the basis of the Mie theory of single scatter. This lends further support to the applicability of the Pitts-Giovanelli method to model systems of this type.
Harry G. Hecht, "The Anisotropy Factor in Dense Scattering Media," Appl. Spectrosc. 34, 157-160 (1980)