title: A robust comparison of dynamical scenarios in a glass-forming liquid.
abstract: We use Bayesian inference methods to provide fresh insights into the sub-nanosecond dynamics of glycerol, a prototypical glass-forming liquid. To this end, quasielastic neutron scattering data as a function of temperature have been analyzed using a minimal set of underlying physical assumptions. On the basis of this analysis, we establish the unambiguous presence of three distinct dynamical processes in glycerol, namely, translational diffusion of the molecular centre of mass and two additional localized and temperature-independent modes. The neutron data also provide access to the characteristic length scales associated with these motions in a model-independent manner, from which we conclude that the faster (slower) localized motions probe longer (shorter) length scales. Careful Bayesian analysis of the entire scattering law favors a heterogeneous scenario for the microscopic dynamics of glycerol, where molecules undergo either the faster and longer or the slower and shorter localized motions.
authors.affiliation: Grup de Caracterització de Materials, Departament de Física i Enginyeria Nuclear, ETSEIB, Universitat Politècnica de Catalunya, Diagonal 647, E-08028 Barcelona, Catalonia, Spain. luis.carlos.pardo@upc.edu.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vispa
authors.forename: Sebastian
authors.initials: S
authors.lastname: Busch
authors.forename: Josep Lluis
authors.initials: JL
authors.lastname: Tamarit
authors.forename: Tobias
authors.initials: T
authors.lastname: Unruh
authors.forename: Felix
authors.initials: F
authors.lastname: Fernandez-Alonso
authors.forename: Luis Carlos
authors.initials: LC
authors.lastname: Pardo