# How to install Charmm36m to gromacs 2022?

**URL:** <https://gromacs.bioexcel.eu/t/how-to-install-charmm36m-to-gromacs-2022/6209>\
**Category:** User discussions\
**Tags:** forcefield\
**Created:** [April 17, 2023, 9:06am UTC](https://gromacs.bioexcel.eu/t/how-to-install-charmm36m-to-gromacs-2022/6209 "2023-04-17T09:06:02Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Joseph](https://avatars.discourse-cdn.com/v4/letter/j/dc4da7/32.png) [@Joseph](https://gromacs.bioexcel.eu/u/Joseph)\
**Post date:** [April 17, 2023, 9:06am UTC](https://gromacs.bioexcel.eu/t/how-to-install-charmm36m-to-gromacs-2022/6209/1 "2023-04-17T09:06:02Z")

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GROMACS version: 2022  
GROMACS modification: No

Can anyone provide a protocol as to how to properly install the charmm36m force field from [MacKerell Lab](http://mackerell.umaryland.edu/charmm_ff.shtml#gromacs)

 ![image](https://europe1.discourse-cdn.com/flex017/uploads/bioexcel1/original/2X/6/62d9009fd7b9616ac9667e44849e9964b3d41627.png)

I copied the unzipped folder to C:\Program Files\GROMACS\share\gromacs\top  
however when I use pdb2gmx I do not see the Charmm36m force field, only the Charmm36 force field.

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**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:** [April 17, 2023, 12:46pm UTC](https://gromacs.bioexcel.eu/t/how-to-install-charmm36m-to-gromacs-2022/6209/2 "2023-04-17T12:46:08Z")

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The protein force field included in the release is CHARMM36m, which we consider the standard CHARMM force field at this point.

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<div class="post-metadata">

**Author:** ![Joseph](https://avatars.discourse-cdn.com/v4/letter/j/dc4da7/32.png) [@Joseph](https://gromacs.bioexcel.eu/u/Joseph)\
**Post date:** [April 17, 2023, 5:57pm UTC](https://gromacs.bioexcel.eu/t/how-to-install-charmm36m-to-gromacs-2022/6209/3 "2023-04-17T17:57:02Z")

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Which is the easiest way to verify that it is CHARMM36m instead of the original?

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<div class="post-metadata">

**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:** [April 17, 2023, 6:20pm UTC](https://gromacs.bioexcel.eu/t/how-to-install-charmm36m-to-gromacs-2022/6209/4 "2023-04-17T18:20:48Z")

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I made the port :)

But we record which files got converted in forcefield.doc, and you’ll find:

```auto
aminoacids:
-----------
- toppar_c36_jul22/par_all36m_prot.prm

```

as the first line. So we’re using CHARMM36m for the protein parameters.