A reverse Monte Carlo algorithm to simulate two-dimensional small-angle scattering intensities

Journal of Applied Crystallography, vol. 55, pp. 1592–1602

Abstract

Small-angle scattering (SAS) experiments are a powerful method for studying self-assembly phenomena in nanoscopic materials because of the sensitivity of the technique to structures formed by interactions on the nanoscale. Numerous out-of-the-box options exist for analysing structures measured by SAS but many of these are underpinned by assumptions about the underlying interactions that are not always relevant for a given system. Here, a numerical algorithm based on reverse Monte Carlo simulations is described to model the intensity observed on a SAS detector as a function of the scattering vector. The model simulates a two-dimensional detector image, accounting for magnetic scattering, instrument resolution, particle polydispersity and particle collisions, while making no further assumptions about the underlying particle interactions. By simulating a two-dimensional image that can be potentially anisotropic, the algorithm is particularly useful for studying systems driven by anisotropic interactions. The final output of the algorithm is a relative particle distribution, allowing visualization of particle structures that form over long-range length scales ( i.e. several hundred nanometres), along with an orientational distribution of magnetic moments. The effectiveness of the algorithm is shown by modelling a SAS experimental data set studying finite-length chains consisting of magnetic nanoparticles, which assembled in the presence of a strong magnetic field due to dipole interactions.

Authors 6

1. Lester C. Barnsley

   Australian Nuclear Science and Technology Organisation · Forschungszentrum Jülich · Australian Synchrotron · Heinz Maier-Leibnitz Zentrum

   Affiliation as printed

   Australian Synchrotron, ANSTO, Clayton 3168, Australia

   Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85748 Garching, Germany

2. Nileena Nandakumaran Aachen Lehrstuhl für Experimentalphysik IVc

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-2) and Peter Grünberg Institut (PGI), JARA-FIT, 52425 Jülich, Germany

   Lehrstuhl für Experimentalphysik IVc, RWTH Aachen University, 52056 Aachen, Germany

3. Artem Feoktystov

   Forschungszentrum Jülich · Heinz Maier-Leibnitz Zentrum

   Affiliation as printed

   Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85748 Garching, Germany

4. Martin Dulle

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1), 52425 Jülich, Germany

5. Lisa Fruhner

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1), 52425 Jülich, Germany

6. Mikhail Feygenson

   Forschungszentrum Jülich · European Spallation Source

   Affiliation as printed

   European Spallation Source ERIC, SE-22100 Lund, Sweden

   Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1), 52425 Jülich, Germany