Spreading out of molecules in a simulation of a droplet over a substrate

please always reply to the mailing list, not just individual people. thanks.

I was hoping that a hypothetical liquid would assume a spherical shape in
order to minimise the surface energy.

but what says that you have a non-wetting surface with "random parameters"?

Hence, I defined the LJ potentials with arbitrary parameters.
I am still in a learning phase trying to get used to LAMMPS.

this has nothing to do with LAMMPS, but rather the physics of your system.