Energy and pressure of shearing fluids at different state points - art. no. 021201

Nonequilibrium molecular dynamics simulations are reported at different str ain rates ((gamma) over dot) and thermodynamic state points for a shearing atomic fluid interacting via a Lennard-Jones potential, Our simulations are performed at the Lennard-Jones triple point, a point midway between the tr iple point and the critical point, and a high point closer to the critical temperature. We find that, for the mid-point and high point, the energy and hydrostatic pressures have strain-rate dependencies of (gamma) over dot(2) in contrast to the (gamma) over dot(3/2) dependencies predicted by mode co upling theory. This analytical dependence is consistent with a Taylor serie s expansion of these quantities as powers of the strain rate tensor. Only a t the triple point does the pressure and energy display a nonanalytical dep endence on (gamma) over dot(3/2).