Scattering properties of heterogeneous mineral particles with absorbing inclusions

•Scattering and absorption characteristics of heterogeneous particles are studied.•Computations are performed using the superposition T-matrix method.•Internal aggregation modifies optical properties of heterogeneous mixtures.

We analyze the results of numerically exact computer modeling of scattering and absorption properties of randomly oriented polydisperse heterogeneous particles obtained by placing microscopic absorbing grains randomly on the surfaces of much larger spherical mineral hosts or by imbedding them randomly inside the hosts. These computations are paralleled by those for heterogeneous particles obtained by fully encapsulating fractal-like absorbing clusters in the mineral hosts. All computations are performed using the superposition T-matrix method. In the case of randomly distributed inclusions, the results are compared with the outcome of Lorenz-Mie computations for an external mixture of the mineral hosts and absorbing grains. We conclude that internal aggregation can affect strongly both the integral radiometric and differential scattering characteristics of the heterogeneous particle mixtures.