Tersoff vs Vashishta potential

Dear All,

I use Tersoff and Vashishta potentials which come with LAMMPS to describe interatomic interactions between Si and C.

A box including SiC is equilibrated under PBCs at room temperature. while using Tersoff potential, everything is fine, however, when i use Vashishta potential, atoms start flying. The point is that i use “exactly the same script” (except for the potential function) for both simulations.

I have attached two snapshots which show the situation.

I wonder if anybody can tell me why this happens, and if there is any solution for it.

Kind regards,

Zhen

Tersoff.jpg

Vashishta.jpg

Anders can likely comment.

Steve

It would be helpful if you could provide an example that I can run to see the problem (potential files, script and data files). Hard to say what’s happening without more details.

Both potential don’t necessary work well with all SiC structures.

Anders