Harmonic vs cosine/squared angle

Hello All,

I’m doing some coarse-grained simulations and I’ve noticed that my simulations become unstable if I use a cosine/squared angle potential, however, if I use a harmonic potential they work fine. I was wondering if anyone could give me some insight into why this might occur. My thoughts are since the cosine/squared is softer at the higher angles, it’s allowing the system to blow up.

I’ve included the lammps command file. You can make the assumption that the system is equilibrated.


CG_PDMS.in (1.01 KB)