Using the optimized geometry from TINKER in OpenMM I got forces of the order of 10^2 kJ/mol/nm. After optimizing with OpenMM the final geometry had forces of the order of 10 kJ/mol/nm. If I'm not mistaken the tolerance is for the rms of the gradients, I played around with that changing it from 10^-3...

Thank you for your reply!
Yes, I was to able get a more strict optimization done with TINKER where the rms of the final gradients is of the order of 10^-5. I thought it was just strange that after using the TINKER optimized geometry in OpenMM I still got large forces on the atoms.

Hello, I was recently using OpenMM to do a energy minimization with AMOEBA for a simple H2O-Cl- dimer system. I printed out the energy and the forces for the optimized geometry and I got non-zero forces on the atoms in the optimized geometry. I used the following commands to perform the optimization...