2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/128832The thermal conductivity is calculated with the Helfand-moment method in the Lennard-Jones fluid near the triple point. The Helfand moment of thermal conductivity is here derived for molecular dynamics with periodic boundary conditions. Thermal conductivity is given by a generalized Einstein relation with this Helfand moment. We compute thermal conductivity by this new method and compare it with our own values obtained by the standard Green-Kubo method. The agreement is excellent.Submitted to the Journal of Chemical PhysicsStatistical MechanicsMesoscale and Nanoscale Physicstext