A general superposition solution for electromagnetic scattering by multiple spherical domains of optically active media

•A superposition solution to arbitrary spherical domains is presented.•Spheres can be internal or external to other spheres in the system.•Optically active media at all levels is represented.•The formulation is adopted in the revised MSTM code.

The superposition solution for scattering by a system of optically active spheres is extended to the case where any of the spheres can be located at points that are either internal and external to the other spheres. The sole restriction on the formulation are that a sphere surface cannot be cut by another surface. The formulation has been integrated into the Multiple Sphere T Matrix code, and illustrative calculation results that demonstrate the veracity of the formulation are presented.