Welcome to charmm2gmx’s documentation!

CHARMM2GMX is a Python package and a set of command-line tools for converting CHARMM toppar files to GROMACS force fields. Apart from its main task, several other utilities are implemented for validating and checking GROMACS force field directories, as well as manipulating residue topologies.

This project has been used since July 2021 to create the “official” GROMACS port of the CHARMM additive force field by J. Lemkul. It is however not related or affiliated in any way to the similarly named scripts found at Alexander D. MacKerell’s above mentionend page. Those scripts convert CHARMM stream files produced by CGenFF to GROMACS topologies.

Contents:

• Installing Charmm2GMX
  • Prerequisites
  • Installing from source
• Quickstart
• Command Line Utilities
  • Command line options
• How to Cite
• Some Background Information
  • Differences from the Previous Implementation
  • Force Field Organization
  • Residue Topology
  • CHARMM2GMX Input File
• Charmm2GMX Internals
  • charmm2gmx