Static and dynamic light scattering from liquid crystalline solutions of rodlike macromolecules

It is argued that concentration fluctuations in lyotropic nematics can cause significant scattering of light. We calculate the static structure factor numerically for a nematic suspension of rods in the second virial approximation. An analytical approximation is also given based on a variational principle applied to an integral equation of the Yvon type. The relation between the one-particle distribution function and the usual correlation functions is discussed. An expression is derived for the polarized dynamical structure factor. This yields the initial decay rate which emphasizes the diffusion perpendicular to the director. We show that the contribution from anisotropic scattering is negligible.