# Drude coordinate and topology files **URL:** \ **Category:** User discussions\ **Created:** [August 29, 2025, 6:01pm UTC](https://gromacs.bioexcel.eu/t/drude-coordinate-and-topology-files/12585 "2025-08-29T18:01:26Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![rpsingh](https://avatars.discourse-cdn.com/v4/letter/r/c57346/32.png) [@rpsingh](https://gromacs.bioexcel.eu/u/rpsingh)\ **Post date:** [August 29, 2025, 6:01pm UTC](https://gromacs.bioexcel.eu/t/drude-coordinate-and-topology-files/12585/1 "2025-08-29T18:01:26Z")
GROMACS version: 2025.1 GROMACS modification: No Here post your question Hi All, I am interested in performing simulations using Drude FF. I have small organic molecules for which CHARMM36 files are available and would like to convert those to Drude. I know that CHARMM-GUI has Drude Prepper but that does not accept files for small organic molecules. CHARMM can convert these files to Drude formats but converting those to GROMACS files is an issue. Are there any scripts or tools available that I can use to convert from CHARMM36 to Drude? Any help in this regard will be appreciated. Thanks, Raman ---
**Author:** ![rpsingh](https://avatars.discourse-cdn.com/v4/letter/r/c57346/32.png) [@rpsingh](https://gromacs.bioexcel.eu/u/rpsingh)\ **Post date:** [September 18, 2025, 10:12am UTC](https://gromacs.bioexcel.eu/t/drude-coordinate-and-topology-files/12585/2 "2025-09-18T10:12:11Z")
Can anyone please chime in to help. Thanks, Raman ---
**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\ **Post date:** [September 18, 2025, 2:57pm UTC](https://gromacs.bioexcel.eu/t/drude-coordinate-and-topology-files/12585/3 "2025-09-18T14:57:52Z")
The only mechanism is CHARMM-GUI, but as with anything, it can only handle species that are already part of the force field. If you have something new, you have to manually generate a topology yourself.