The shape influence on the overall single scattering properties of a sample in random orientation

In order to identify the type of scattering profile that corresponds to some specific shapes, we have performed calculations of some scattering properties for those shapes with a fixed size distribution. Aggregates of different numbers of spheres have been used to fit the laboratory measurements of fly ashes. The results for other shapes, such as rectangular prisms with different axial proportions, particles made of joined cubes, and particles with different fluffiness, are also shown. From all these calculations, it is concluded that the size-averaged scattering matrix elements resembles Rayleigh features, for the size distribution stopping at 1.0μm, when either the number of spheres or cubes of the aggregates is increased, the shape becomes flatter or the particles become fluffier. We also show the effect of the refractive index on the Qsca vs. X curve in the case of strongly absorbing particles. A tendency to reach the geometric optic regime is observed instead of the Rayleigh regime using the same size distribution.

Research highlights► The overall scattering properties of a sample in random orientation. ► To study how the influence of the particle shape works. ► To study the interference patterns and the overlapped ripples on the Qsca curves. ► To study a Rayleigh-like behaviour on the size-averaged scattering matrix elements.