Form and structure factors, interactions, modeling

Jan Skov Pedersen

The lecture will deal with the classical modeling approach for analysis of small-angle scattering data. In the first part, analytical models are considered, and in a second part, effects of inter-particle interactions are described.

An overview over the form factors of various simple geometrical objects like spheres, ellipsoids, cylinders, discs etc will be given. A few examples are treated in greater detail. In addition, the form factors of polymer models with many internal degrees of freedoms are given, also with a few examples treated in detail. It will be shown how form factors of object consisting of spherical subunits can be derived and similarly how form factors of polymer-like branched structures can be calculated for pre-defined structures. Also models consisting of both spherical and polymer chain subunits will be discussed. It will be described how one can use of Monte Carlo simulations for generating form factors of complex structures for which an analytical calculation is not possible.

In the last part of the lectures, the effects of inter-particle interactions are discussed. The main analytical results will be given for spherical particles and polymer-like particles; approximations valid for particles with some anisotropy are also described.

Throughout the lectures, examples of applications to experimental data are included.

J. Skov Pedersen (1997) Analysis of Small-angle Scattering Data from Polymeric and Colloidal Systems: Modelling and Least-squares Fitting. Advances in Colloid and Interface Science 70, 171-201.
J. Skov Pedersen (2002) Monte Carlo Simulation Techniques Applied in the Analysis of Small-Angle Scattering Data from Colloids and Polymer Systems. Editors: Peter Lindner and Thomas Zemb. Neutrons, X-Rays and Light, 381-389. Elsevier.
J. Skov Pedersen (2002) Modelling of Small-Angle Scattering Data from Colloids and Polymer Systems. Editors: Peter Lindner and Thomas Zemb. Neutrons, X-Rays and Light, 391-420. Elsevier.
K.K. Andersen, C.L.P. Oliveira, K.L. Larsen, F.M. Poulsen, T.H. Callisen, P. Westh, J. Skov Pedersen, D.E. Otzen (2009) The Role of Decorated SDS Micelles in Sub-CMC Protein Denaturation and Association. Journal of Molecular Biology, 391(1), 207-226.

Date/time: Sunday, 21 October 2012, 9:30