Forward scattering of light, X-rays and neutrons

Abstract

The central points of this paper can now be summarized. We consider here, for simplicity only, vanishing particle concentration. In equilibrium sedimentation equation (6) applies. The density increment is a measurable quantity. It can either be introduced into equation (6) to calculateM₂, or it can be analysed by equations (7) and (8) to provide additional information on specific volumes and solute interactions.Light scattering is determined by the analogous equation (20). The refractive index increment is also experimentally accessible and its structure (not considered here) is similar to that of the density increment. Small angle X-ray scattering is determined by equation (31) and the electron density increment which appears in this equation cannot be directly determined by experiment. Yet it can be obtained in straightforward fashion from the mass density increment, by equation (34). Similarly, in the case of neutron scattering (equation (38)), the scattering length density increment is obtained from the mass density increment by equation (40), or it may now be directly evaluated by neutron interferometry.