[lammps-users] Importance of pressure in NVE or NVT equilibration

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1

Hi Everybody,
I am trying to predict the mass density of a methane system in liquid phase (e.g. 100 bar and 180 K condition). The initial configuration is generated using the VMD TopoTools plugin according to the target density. For equilibration of the system, I am going to run NVE or NVT simulations. Usually in such simulations we consider the system equilibrated when the energy or temperature is converged. But I’d like to know if I need to check the pressure as well. To me, it might be also important to see if the (average) pressure matches the desired one before running the NPT simulations. Any comments and suggestions on this matter are greatly appreciated.

Thanks.

2

Monitoring (averaged) pressure is a good thing. However, whether this will result in the desired value strongly depends on the choice of force field parameters.
Out of temperature, density and pressure, you can only set two. The third will be determined by the force field and how well it is suited to model your system at the chosen conditions.

Axel.