TY  - JOUR
AU  - Gommes, Cedric
AU  - Zorn, Reiner
AU  - Jaksch, Sebastian
AU  - Frielinghaus, Henrich
AU  - Holderer, Olaf
TI  - Inelastic neutron scattering analysis with time-dependent Gaussian-field models
JO  - The journal of chemical physics
VL  - 155
IS  - 2
SN  - 1089-7690
CY  - Melville, NY
PB  - American Institute of Physics
M1  - FZJ-2021-02993
SP  - 024121 -
PY  - 2021
AB  - 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
LB  - PUB:(DE-HGF)16
C6  - 34266279
UR  - <Go to ISI:>//WOS:000692373500006
DO  - DOI:10.1063/5.0053446
UR  - https://juser.fz-juelich.de/record/894027
ER  -