CHARMM Force Field
to download click on link
CHARMM36 Files for GROMACS
CHARMM36 force field in GROMACS format, including CGenFF version 4.6 and the CHARMM36m protein force field revision. Updated July 2022.
The current version of the CHARMM36 port for GROMACS is dated July 2022, corresponding to the CHARMM toppar release of the same date. It contains the same topologies and parameters as the July 2021 update (including the option to use LJ-PME with lipids, given in the second port listed below) and adds some new parameters, and modified amino acids, among other items. See the "toppar_history" file in the CHARMM toppar distribution above for details. Files updated 12/8/2022 to fix typos related to TIP4P-Ew water parameters and an issue related to cholesterol NBFIXes.
charmm36-jul2022.ff.tgz this one