Dear Lammps Users,
I am have quick question regarding implementing WCA potential in lammps. For those who are not aware of it, It is essentially LJ 12-6 potential with additional epsilon added to it. It is generally used as a repulsive interactions with a cutoff at sigma*2^(1/6) (the distance at which interaction is negative epsilon). So basically the total interaction becomes zero at this distance.
I tried to look for various pair styles but I could find something like it. If I use lj/cut or lj/expand (for particles of different size) with the cutoff at sigma2^(1/6), I get the interaction energy as “-epsilon”. One option is to use pair_modify shift yes to move the interaction to zero. However, the problem with it is that it doesn’t modify the forces. So, for the distances between (sigma and sigma2^(1/6), the particles would feel attractive interaction).
This potential is often used to repulsive interactions between unlike atoms. It may be possible that I might be overlooking a particular pair_style.
I will highly appreciate if anyone could help me out here.
Regards and thanks in advance.