There is a problem has been bothering me for a long time.I want to use lammps to calculate thermal conductivity of molecular like water.
There are two methods (NEMD and EMD )calculating thermal conductivity.
if we use EMD like Green-Kubo, the thermal conductivity of water overestimates experiment values of water so much(30%-50%). However if we use NEMD like fix Heat or fix thermal/conductivity command(RNEMD), the energy of system is not conserved,the energy is increasing slowly.
So I really want to know if we can use lammps to calculate thermal conductivity of molecular,because lammps was designed for atomic systems not molecular ones.
Looking forward to your reply!