Dear Lammps Developer and users,
I’m working on REAXFF with p p f boundary conditions and wanted to know if it’s possible to achieve 1atm or anything that is in the reasonable range. Will minimization command help to achieve it? I’m not using it since I’m running the equilibrium step for a much longer time. I’m getting pressure fluctuations as press =907.18867 pxx= -2357.0153 pyy= -3339.7149 pzz=8418.2962.
Pressure fluctuates. And it fluctuates more for small systems and less compressible systems. Most condensed matter is not very compressible. All of this is independent of the force field in use. This has been discussed many times before, so my suggestion is that you study those old discussions first and - in case there are still open questions after that - come back with more specific information about your system and why you believe that the pressure is not physical or reasonable.
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Thank you for your quick response. I will look for previous questions regarding this.
Also, I have a question about applying e-field. What are the units that are being used in Reaxff? If I want to apply 25MeV/cm, would the magnitude be 0 0 5.755 in the fix e-field command? I got the conversion from reaxff_deffs.h of the source file.
As per documentation (fix efield command — LAMMPS documentation) you should use electric field units. For units real (units command — LAMMPS documentation) that is volts per angstrom.
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