LIGHT-SCATTERING FROM IRREGULAR TETRAHEDRAL AGGREGATES

We examine the light scattering from spheres aggregated into tetrahedr al structures and the changes that occur when the internal structure o f the system is modified by filling the central portion of the tetrahe dron with an index-matching solution. Several effects are noticed in t he scattering signals. The scattering phase function of aggregates is quite sensitive to changes in the internal structure within the aggreg ate. The positions and relative intensities of the maxima and minima o f an aggregate tend to have a stronger dependence on orientation and i nternal structure than for a sphere containing an inclusion. As the ar ea of the interfaces increases, the backscatter intensity increases, r esulting in a decrease in the asymmetry parameter. Specular reflection s also occur due to the constructive interference of rays reflecting o ff the different lattice sites. (C) 1998 Elsevier Science B.V. All rig hts reserved.