From: Seth Axen (
Date: Tue May 17 2016 - 13:23:41 CDT

   I am using ffTK to fit several dihedral parameters. For several of my
molecules, through iterative sampling, I am able to fit the MM potential
energy surface curve to the shape of the QM curve. Generally, the global
minima also match in height. However, additional simulated annealing or
downhill, regardless of the tolerance, is unable to fit the heights of the
curves. I was hoping someone could shed some light on what might be the
cause of this. Attached is an example.