2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/128831We propose a new method, the Helfand-moment method, to compute the shear viscosity by equilibrium molecular dynamics in periodic systems. In this method, the shear viscosity is written as an Einstein-like relation in terms of the variance of the so-called Helfand moment. This quantity, is modified in order to satisfy systems with periodic boundary conditions usually considered in molecular dynamics. We calculate the shear viscosity in the Lennard-Jones fluid near the triple point thanks to this new technique. We show that the results of the Helfand-moment method are in excellent agreement with the results of the standard Green-Kubo method.Submitted to the Journal of Chemical PhysicsStatistical MechanicsMesoscale and Nanoscale Physicstext