Dear all,

First of all apologies for a long mail.

I am trying to calculate thermal conductivity of a molecular melt using the RNEMD (Mu ̈ller-Plathe JCP 1997 & Zhang JPC 2005) method implemented in LAMMPS.

I work with real units and thus have the following conversion,

-----------(1)

-----------(2)

**Real units**

Energy: kcal/mol

*(fix thermal/conductivity: This fix computes a global scalar which can be accessed by various output commands. The scalar is the cumulative kinetic energy transferred between the bottom and middle of the simulation box (in the edim direction) is stored as a scalar quantity by this fix. This quantity is zeroed when the fix is defined and accumulates thereafter, once every N steps. The units of the quantity are energy; see the units command for details. The scalar value calculated by this fix is “intensive”.)*

Lx: Angstrom (10^-10 m)

time: fs (10-15 s)

Temperature: K

1 kcal/s = 4184 Watts

1mol = (N/N_A)

N is the total number of molecules in the system and N_A the Avogadro’s number.

I am not sure about this unit conversion. Could someone comment on it?

**Here is the lammps input file,**