Re: [lammps-users] Soft repulsive Gay-Berne potential in LAMMPS

Jumping into this conversation.

The potential that you have modified is not “soft”, as it will still go to infinity for r->0. You removed the repulsive part, which I think will make your simulations highly unstable.

To check that you have implemented the new pair style correctly, I suggest a compute that my colleague Matteo Ricci developed for the MOLC package (yet to be released!). You can find it here: https://github.com/matteoeghirotta/lammps-30Oct19/tree/master/src/USER-MOLC

This includes a new “compute pair/local/numeric” using numerical gradients to compute forces and torques. It is of course computational overkill, but quite useful to debug new potential styles. I hope one day we’ll be able to push all this stuff into the official Lammps distribution.

Meanwhile, I remind that we are also developing our own flavour of soft Gay-Berne potential, which depends on the extra parameters \alpha and \lambda, analogous to the style lj/cut/coul/long/soft. Once tested, I think we will make it available through the USER-FEP package.

I hope that helps.
Otello