title: The non-Gaussian dynamics of glycerol.
abstract: We have combined incoherent quasielastic neutron scattering experiments and atomistic molecular simulations to investigate the microscopic dynamics of glycerol moving away from the hydrodynamic limit. We relate changes in the momentum transfer (Q) dependence of the relaxation time to distinct changes of the single-particle dynamics. Going from small to large values of Q, a first crossover at about 0.5 Å(-1) is related to the coupling of the translational diffusion dynamics to the non-Debye structural relaxation, while the second crossover at a Q-value near the main diffraction peak is associated with the Gaussian to non-Gaussian crossover of the short-time molecular dynamics, related to the decaging processes. We offer an unprecedented extension of previous studies on polymeric systems towards the case of the typical low-molecular-weight glass-forming system glycerol.
authors: Institute of Physics of Rennes, CNRS-University of Rennes 1, UMR 6251, F-35042 Rennes, France.
authors: R
authors: R
authors: Busselez
authors: R
authors: R
authors: Lefort
authors: A
authors: A
authors: Ghoufi
authors: B
authors: B
authors: Beuneu
authors: B
authors: B
authors: Frick
authors: F
authors: F
authors: Affouard
authors: D
authors: D
authors: Morineau
mesh_terms: D004058:Diffusion; D005990:Glycerol / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D016011:Normal Distribution; D013696:Temperature
chemical_list: D005990:Glycerol