Mie Scattering Formulae for Non-spherical Particles

Abstract

A natural extension of the Mie formulae using first-order perturbation theory is presented. The assumption is that the particle be homogeneous and smooth and not deviate far from sphericality. The key to the method is the expansion of angular functions, related to the geometry of the particle, in the same way as the angular dependence of the Hertz-Debye potentials. Formulae bearing close resemblance to the zero-order ones encountered in Mie scattering theory are derived and full-field pictures of the angular intensity distribution are produced in a few different cases for small particles (diameter ⋍ λ). Limitations of the method are discussed.