The 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.Comment: Submitted to the Journal of Chemical Physic