Efficient viscosity estimation from molecular dynamics simulation via momentum impulse reaxation

摘要

A new momentum impulse relaxation method for obtaining the shear viscosity of Newtonian fluids using molecular dynamics simuations is introduced. The method involves the resoolution of decaying coarse-grain Gaussian velocity profile in a properly thermostate simulation box. This localized velocity profile,along with a modification of the periodic boundary conditions, allows computations in a periodic box with minimal phonon feedback due to periodicity. The short-time decay of te small-amplitude velocity profile yields shear viscosities for atomic and molecular species that are in quantiative agreement with those obtained using conventional techniques,but with more than an order of magnitude reduction in computational effort.