title: Crossover between short- and long-time behavior of stress fluctuations and viscoelasticity of liquids.
abstract: An effective viscosity coefficient is introduced based on definite time averages of equilibrium stress fluctuations rather than stress correlations. Analysis of this quantity via molecular dynamics of a simple model liquid reveals a crossover between the expected short-time elastic and the long-time viscous behavior with increasing averaging time. The procedure allows us to extract the zero-rate shear viscosity when the averaging time becomes one order of magnitude larger than the relevant relaxation time. A relationship between this effective viscosity and the dynamic viscosities is established.
authors.affiliation: Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstrasse 36, Germany.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Hess
authors.forename: Martin
authors.initials: M
authors.lastname: Kröger
authors.forename: Denis
authors.initials: D
authors.lastname: Evans