[lammps-users] How to set the pressure of NEB process

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Dear LAMMPS users,

I’m trying to assess the effect of pressure on migration barriers. My goal is to compute migration barriers at various pressures. I tried to minimize my system prior to the NEB calculation using fix box/relax at a desired pressure. The system relaxed at that pressure but, during the NEB process, while the volume remained constant, the pressure deviated considerably from the desired value.

Is there a way to control the pressure during the NEB process so as to be sure that the barriers we get correspond to the defined pressure?

Regards,

Jehiel

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I don’t know how you are are monitoring the pressure during NEB. Each replica would
have its own pressure in its log file I suppose. But you should not be trying to run
NPT during NEB, just NVE, i.e. constant volume, as it is effectively a minimization process.
So I don’t think the pressure during NEB is relevant.

I suggest you equilibrate to a desired pressure before NEB, then switch to NVE and run NEB.
The barrier NEB gives will be the barrier at the desired pressure. I.e. for a system with atoms
slightly compressed or expanded.

Steve