Hello all,

I am trying  to model structures like pyrene or two connected benezene ring kind  structures i am getting very postive energies and that too the contribution from torsion energies are very high. I tried pcff,cvff, Drieding force fileds also. What could be the error?? and how to model these type of structures.

for example :

  Operation: minimize

  Minimization Method/Stage:

    CG (Fletcher-Reeves).

  Step             1

  Maximum derivative: 80.071

  CPU Time   0:00:00

    463.28  Potential (kcal/mol)

  --------

      2.53  Electrostatic

     31.46  vdW Repulsive

    -25.69  vdW Dispersive

      0.00  Hydrogen Bond

      8.30  Nonbond (Total)

  --------

     10.29  Angle

    113.04  Bond

   301.26  Torsion

      0.01  Out-of-Plane