Cross-correlation laser scattering

Abstract

Cross-correlation between two detectors was applied to analyze laser light-scattering fluctuations. Laser scattering from random concentration fluctuations is spatially coherent over small angular areas that are inversely proportional in size to the dimension of the scattering volume. By cross-correlating scattering intensity fluctuations in different angles, the correlation due to relaxation of concentration fluctuations is practically eliminated, and correlations reflecting changes in the scattering from the individual particles can be enhanced. Rotational diffusion of assymetric particles, conformational relaxation of random coils, and association-dissociation dynamics are determined here using the above approach.

Two-dimensional structure from random multiparticle X-ray scattering images using cross-correlations

“…Wochner et al 27 have used the diagonal 2-point CC, derived from synchrotron X-ray coherent diffraction data from highly concentrated suspensions of PMMA nanospheres, to identify the preferential symmetry of 3D clusters 25 that form temporarily within the sample. Regarding possible future investigations on 3D structural features of macromolecules or other particles in solution, which exploit the brilliance of XFEL radiation sources, it appears that applying the CC method in the spirit of its original formulation 13 is a suitable approach; dynamical information may be accessed through the straightforward generalization of the CC analysis to laser pump/X-ray probe scattering images, or even to scattering data obtained with X-ray split-and-delay data 28,29 . The present 2D demonstration experiment and its discussion have direct relevance to the 3D case, regarding the effects of interparticle interference and of the unavoidably non-uniform beam intensity profile, as well as the independence of the signal-to-noise from the average number of scattering particles.…”

Static and dynamic light scattering by aerosols in a controlled environment

“…In contrast, the multiple scattering problem was otherwise dealt with, either theoretically (Dhont and de Kruif, 1983) or experimentally using novel short path length scattering cells (Cummins and Staples, 1981). Kam and Rigler (1982) used cross-correlation of scattered in-tensity at different angles between two detectors to eliminate contributions from concentration fluctuations. As a result, scattering from individual particles was enhanced.…”

Recent Advances in Fluorescence Cross-correlation Spectroscopy

“…The signals from both detector channels are cross-correlated and the doubly labeled products can be easily distinguished from the singly labeled reactants, independent of their mass. Earlier crosscorrelation systems have made use of light scattering or a combination with fluorescence to measure their cross-correlation functions and determine rotational diffusion and association-dissociation kinetics [20,21]. Although the concept of dual-color fluorescence cross-correlation spectroscopy (FCCS) has been proposed for biotechnological applications [22], it was first experimentally realized by Schwille and co-workers to measure nucleic acid hybridizations [23].…”