Two-dimensional mathematical treatment of small-angle light scattering from a system of periodic rod-medium structures

Abstract

A theory for small-angle light scattering (SALS) from assemblies of rods has been formulated in order to study the effect of the I_B and I_C terms, as defined by Hosemann and Blundell for small-angle X-ray scattering (SAXS), on the scattered intensity. The scattering patterns computed for the H_v polarization condition in terms of a model having two-dimensional oriented rods. The scattering lobes were hardly affected by the I_C terms and the shape of the lobes was similar to that calculated for scattering from an isolated rod. In contrast, the I_C term caused a significant change in the scattered intensity distribution around the sharp streaks associated with the effect of interparticle interference caused by the arrangement of the centre of gravity of the rods. Therefore it is concluded that the I_C term must be included when calcuating the scattering pattern, except when the number of rods is very large and the I_B term is approximately equal to the scattered intensity. This is the same result as has been obtained for SAXS.