Shear viscosities away from the melting line: A comparison of equilibrium and nonequilibrium molecular dynamics

Journal Article · Fri Apr 15 04:00:00 EST 1983 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.445384· OSTI ID:6235617

Holian, B L; Evans, D J

Doubts about the validity of the nonequilibrium molecular dynamics (NEMD) methods of computing shear viscosity have persisted, partly because of the apparent disagreement (approx.25%) between NEMD and equilibrium Green--Kubo (GK) results for the Lennard-Jones system near its triple point. This region of the phase diagram near the melting line is the so-called ''molasses'' regime where the tail of the shear-stress autocorrelation function is quite large, deviating from ''exponential'' decay at a level of about 10%. In order to see whether the effects of the ''molasses tail'' might be obscuring a more profound difference between NEMD and GK results, we have carried out independent NEMD and GK calculations for a state in the LJ fluid far away from this troublesome molasses region, namely at a temperature twice critical and a density between the triple and critical points. We find the NEMD and GK results for the linear shear viscosity to be in good agreement.

• Research Organization: University of California, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 6235617
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 78:8; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CRITICAL TEMPERATURE
DIAGRAMS
EQUILIBRIUM
FLUIDS
LENNARD-JONES POTENTIAL
LIQUIDS
MELTING
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POTENTIALS
SOLIDS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
VISCOSITY