The CHARMM General Force Field (CGenFF) program performs atom typing and assignment of parameters and charges by analogy in a fully automated fashion. Atom typing is done by a deterministic programmable decision tree. Assignment of bonded parameters is based on substituting atom types in the definition of the desired parameter. A penalty is associated with every substitution and the existing parameter with the lowest total penalty is chosen as an approximation for the desired parameter; the "penalty score" is returned to the user as a measure for the accuracy of the approximation. Charges are assigned using an extended bond-charge increment scheme that is able to capture short- and medium-range inductive and mesomeric effects.
The CGenFF program is a product of the discontinued ParamChem project. Future directions for the CGenFF program can be found at the future prospects page.
CGenFF program links
- Usage information.
- Summary of output data and its utilization (required reading).
- FAQ (read this before contacting us with questions).
- How to cite / references.
CGenFF force field links
- Latest CGenFF version (required for using the output of the CGenFF program).
- Introduction.
- FAQ.
- Parameter optimization tutorial
- How to cite / references.
- The CHARMM forums provide additional resources on how to accomplish common and less common tasks using CHARMM. Specifically, there is a script archive with recommended procedures, a basic questions forum, and last but not least, a parameter set discussion forum that is frequented intermittently by the CGenFF authors.
