[lammps-users] Water droplet on Titanium surface

Dear Lammps users,

I am trying to simulate a spherical droplet water spreading on the titanium surface using the Reaxff force field in the NVT ensemble. When I run the simulation, the water explodes. I tried to increase the simulation time (600ps), run at low temperature (100K), but the problem occurs again. Does anyone know what my problem is? Any suggestion?
Best regards,
Enzo Claudino

Dear Lammps users,

I am trying to simulate a spherical droplet water spreading on the titanium surface using the Reaxff force field in the NVT ensemble. When I run the simulation, the water explodes. I tried to increase the simulation time (600ps), run at low temperature (100K), but the problem occurs again. Does anyone know what my problem is? Any suggestion?

It is extremely difficult to provide meaningful advice on such limited information.

You have to explain a bit more what you mean by “explode”, perhaps provide a small(!) input deck and log file for a small test system.
The most common mistakes are using a bad initial geometry (and without minimization), the wrong units setting, or using a ReaxFF potential file with parameters that are not suitable for the system in question (ReaxFF parameterizations are very specific to systems and environment and thus even less transferable than other classical force fields).

Some evaporation is to be expected for such a droplet simulation unless you are way below the freezing point of water. It may be helpful to experiment with that kind of simulation by setting up a simulation of a droplet using a conventional water potential (TIP3P, SPC/E, TIP4P) on an immobile LJ lattice surface or a simple (flat) wall potential.

Axel.

Thanks Axel,
I will follow the suggestion and check my geometry (I used the minimization in my system) and ReaxFF, your suggestion on the use of conventional water potential and the LJ lattice is interesting, I will follow it too.
Enzo