Analytic dependence of the pressure and energy of an atomic fluid under shear.

Nonequilibrium molecular dynamics simulations are reported at different strain rates (gamma;) for a shearing atomic fluid interacting via accurate two- and three-body potentials. We report that the hydrostatic pressure has a strain-rate dependence of gamma;(2), in contrast to the gamma;(3/2) dependence predicted by mode-coupling theory. Our results indicate that the pressure and energy of real fluids may display an analytic dependence on the strain rate. This is in contrast to previous work using either Lennard-Jones or Weeks-Chandler-Anderson potentials that had shown a gamma;(3/2) dependence of pressure and energy.