Optical properties of a dispersion of anisotropic particles with non-randomly distributed orientations. The case of atmospheric ice crystals

The orientational distribution of the particles in a dispersion plays an im portant role in determining the optical properties of the dispersion as a w hole. Since assessing the reliability of an assumed orientational distribut ion requires calculating an ensemble average over the particles concerned, we examine a few cases of orientational distributions that allow for analyt ical calculation of the average in the framework of the transition matrix a pproach. Explicit formulas are given and applied to the calculation of the forward-scattered and backscattered intensity from dispersions of model par ticles meant to simulate the optical behavior in the infrared of the atmosp heric ice crystals that occur as hexagonal platelets. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.