ChemDraw Chem3D: Which version of MM2 is being used in Chem3D

Which version of MM2 is being used in Chem3D?

We are using a tweaked version of the MM282 parameter set. Chem3D obtains data for the MM2 calculations from the MM2 parameter tables. The bulk of these parameters were provided by Dr. N.L. Allinger. Several additional parameters were provided by Dr. Jay Ponder, author of the Tinker program. Some commonly used parameters not provided by them were provided by CambridgeSoft, however, most of these CambridgeSoft parameters are estimates which are extrapolated from other parameters.