%0 Journal Article
%A Gommes, Cedric
%A Zorn, Reiner
%A Jaksch, Sebastian
%A Frielinghaus, Henrich
%A Holderer, Olaf
%T Inelastic neutron scattering analysis with time-dependent Gaussian-field models
%J The journal of chemical physics
%V 155
%N 2
%@ 1089-7690
%C Melville, NY
%I American Institute of Physics
%M FZJ-2021-02993
%P 024121 -
%D 2021
%X Converting neutron scattering data to real-space time-dependent structures can only be achieved through suitable models, which is particularly challenging for geometrically disordered structures. We address this problem by introducing time-dependent clipped Gaussian field models. General expressions are derived for all space- and time-correlation functions relevant to coherent inelastic neutron scattering for multiphase systems and arbitrary scattering contrasts. Various dynamic models are introduced that enable one to add time-dependence to any given spatial statistics, as captured, e.g., by small-angle scattering. In a first approach, the Gaussian field is decomposed into localized waves that are allowed to fluctuate in time or to move either ballistically or diffusively. In a second approach, a dispersion relation is used to make the spectral components of the field time-dependent. The various models lead to qualitatively different dynamics, which can be discriminated by neutron scattering. The methods of this paper are illustrated with oil/water microemulsion studied by small-angle scattering and neutron spin-echo. All available data—in both film and bulk contrasts, over the entire range of q and τ—are analyzed jointly with a single model. The analysis points to the static large-scale structure of the oil and water domains while the interfaces are subject to thermal fluctuations. The fluctuations have an amplitude of around 60 Å and contribute to 30% of the total interface area
%F PUB:(DE-HGF)16
%9 Journal Article
%$ 34266279
%U <Go to ISI:>//WOS:000692373500006
%R 10.1063/5.0053446
%U https://juser.fz-juelich.de/record/894027