Themostatting walls for calculating thermal conductivity.

Hello all,

I’m new to MD and LAMMPS. I’m trying to calculate the thermal conductivity of tip3p water model, in between two fcc lattice walls (a channel, basically). I would like to know how to thermostat the walls properly. I’ve been trying out various thermostatting techniques available in lammps but I’m not able to get to the equlibration point.

This is what I do :

my boundary is p p f, (used f because of the kspace solver with pppm)
used the typical sigma and epsilon values for tip3p model(including bond and angle parameters),
A spring/self potential for the walls.
set a temperature of 303K using the velocity command for the walls and water region.
Then minimized the energy of the system.
------hope up to here, nothing is wrong-------

Now, I was confused in choosing a thermostat. On referring to certain literature I found that the NVT would be fine, but I have got non-periodic boundary condition, so I guess the canonical ensemble would not be followed. I tried using the NVT command just for the liquid region, but the temperature of the system does not increase beyond 234K. I tried using fix langevin + nve and still, there isn’t much of a difference. I also tried the fix temp/rescale + nve, the system superficially looks equilibriated but the results (density/temperature profiles) were incorrect.

In theory i guess using a fix langevin + nve should work fine, right? Is it advisable to use a fix temp/rescale for the walls with this ?

yours sincerely,