Structure of a sheared soft-disk fluid from a nonequilibrium potential.

The distortion of structure of a simple, inverse-12, soft-disk fluid undergoing two-dimensional plane Couette flow was studied by nonequilibrium molecular dynamics (NEMD) simulation and by equilibrium Monte Carlo (MC) simulation with a nonequilibrium potential, under which the equilibrium structure of the fluid is that of the nonequilibrium fluid. Extension of the iterative predictor-corrector method of [Phys. Rev. A 33, 3451 (1986)]] was used to extract the nonequilibrium potential with the structure input from the NEMD simulation. Very good agreement for the structural properties and pressure tensor generated by the NEMD and MC simulation methods was found, thus providing the evidence that nonequilibrium liquid structure can be accurately reproduced via simple equilibrium simulations or theories using a properly chosen nonequilibrium potential. The method developed in the present study and numerical results presented here can be used to guide and test theoretical developments, providing them with the "experimental" results for the nonequilibrium potential.