Merck Molecular Force Field

Merck Molecular Force Field (MMFF) is a family of force fields developed by Merck Research Laboratories. They're based on MM3 force field. MMFF is not optimized for a single use (like simulating proteins or small molecules), but tries to perform well for a wide range of organic chemistry calculations. The parameters in the force field have been derived from computational data.

The first published force field in the family (MMFF94) was described in ''Thomas A. Halgren. Merck molecular force field. I. Basis, form, scope, parameterization, and performance of MMFF94''.

A set of molecular structures and the corresponding output of Halgren's MMFF94 implementation is provided at the Computational Chemistry List (http://server.ccl.net/cca/data/MMFF94/) for validation of other MMFF implementations.