MIE SCATTERING FROM ANISOTROPIC THICK SPHERICAL-SHELLS

A theory of the electromagnetic scattering from spherical shells compo sed of radially oriented optically anisotropic scattering elements is presented. The theory is valid for arbitrary shell size and index of r efraction but is limited to moderate shell thickness compared to the s hell radius. The theory includes the effect of the shell thickness to second order, thereby extending previous work by Lange and Aragon [J. Chem. Phys. 92, 4643, (1990)]. Exact closed form solutions could be ob tained for some, but not all of the terms in the expansion. Extensive comparisons with exact numerical computations based on infinite series of non-integral order Bessel functions are included, as well as compa risons with the exact closed form expressions of the first order theor y. The relationship of the second order theory to the Rayleigh-Debye a pproximation is examined and it is shown that, in contrast to the firs t order case, there are Mie corrections to the effects of the optical anisotropy on the scattering amplitudes. These results ace useful in t he interpretation of light scattering experiments from phospholipid ve sicle dispersions.