A computationally efficient superposition T-matrix method for non-spherical particles with overlapping minimum circumscribing spheres

Multiple scattering of particles is calculated with the superposition T-matrix method even if their minimum circumscribing spheres overlap. Starting from the T-matrix of arbitrarily shaped particles, mutual interactions are computed using, exclusively, addition theorems for spherical vector waves. Although a similar idea has been published recently for the two-element case, its extension to an arbitrary number of particles can be very complicated and even unfeasible. In this work, a new, more efficient approach is proposed that provides practically the same results. In addition, it allows its easy application to an arbitrary number of particles simultaneously with the classical superposition T-matrix formulation.