# Addition of AMBER OL3 Force field in GROMACS

**URL:** <https://gromacs.bioexcel.eu/t/addition-of-amber-ol3-force-field-in-gromacs/13726>\
**Category:** User discussions\
**Created:** [September 17, 2026, 12:53pm UTC](https://gromacs.bioexcel.eu/t/addition-of-amber-ol3-force-field-in-gromacs/13726 "2026-09-17T12:53:39Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Nainsybaghel](https://avatars.discourse-cdn.com/v4/letter/n/9fc29f/32.png) [@Nainsybaghel](https://gromacs.bioexcel.eu/u/Nainsybaghel)\
**Post date:** [September 17, 2026, 12:53pm UTC](https://gromacs.bioexcel.eu/t/addition-of-amber-ol3-force-field-in-gromacs/13726/1 "2026-09-17T12:53:39Z")

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GROMACS version:  
GROMACS modification: Yes/No  
Here post your question

**Command line:**

gmx pdb2gmx -f 1AKI\_clean.pdb -o 1AKI\_processed.gro -water tip3p

**Output:**

Select the Force Field:  
From ‘/usr/local/gromacs/share/gromacs/top’:  
1: AMBER03 protein, nucleic AMBER94 (Duan et al., J. Comp. Chem. 24, 1999-2012, 2003)  
2: AMBER94 force field (Cornell et al., JACS 117, 5179-5197, 1995)  
3: AMBER96 protein, nucleic AMBER94 (Kollman et al., Acc. Chem. Res. 29, 461-469, 1996)  
4: AMBER99 protein, nucleic AMBER94 (Wang et al., J. Comp. Chem. 21, 1049-1074, 2000)  
5: AMBER99SB protein, nucleic AMBER94 (Hornak et al., Proteins 65, 712-725, 2006)  
6: AMBER99SB-ILDN protein, nucleic AMBER94 (Lindorff-Larsen et al., Proteins 78, 1950-58, 2010)  
7: AMBERGS force field (Garcia & Sanbonmatsu, PNAS 99, 2782-2787, 2002)  
8: CHARMM27 all-atom force field (CHARM22 plus CMAP for proteins)  
9: CHARMM36 all-atom force field (February 2026)  
10: GROMOS96 43a1 force field  
11: GROMOS96 43a2 force field (improved alkane dihedrals)  
12: GROMOS96 45a3 force field (Schuler JCC 2001 22 1205)  
13: GROMOS96 53a5 force field (JCC 2004 vol 25 pag 1656)  
14: GROMOS96 53a6 force field (JCC 2004 vol 25 pag 1656)  
15: GROMOS96 54a7 force field (Eur. Biophys. J. (2011), 40, 843-856, DOI: 10.1007/s00249-011-0700-9)  
16: OPLS-AA/L all-atom force field (2001 aminoacid dihedrals)

I want to add AMBER OL3 FFs in the option and want to use that. guild me to do so.

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**Author:** ![jindrich.lnenicka](https://avatars.discourse-cdn.com/v4/letter/j/f475e1/32.png) [@jindrich.lnenicka](https://gromacs.bioexcel.eu/u/jindrich.lnenicka)\
**Post date:** [September 22, 2026, 7:47pm UTC](https://gromacs.bioexcel.eu/t/addition-of-amber-ol3-force-field-in-gromacs/13726/2 "2026-09-22T19:47:35Z")

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You need to download ff files from [OL Force Field Refinement for RNA and DNA Simulations](https://fch.upol.cz/ff_ol/gmxOL24.php) and then either copy them to your working folder or to [path to your gromacs installation]/share/gromacs/top/ if you plan to use them regularly. Then it should pop up as an option when choosing FF with automatically assigning OL24 to DNA, OL03 to RNA and ff14sb to proteins.

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**Author:** ![Nainsybaghel](https://avatars.discourse-cdn.com/v4/letter/n/9fc29f/32.png) [@Nainsybaghel](https://gromacs.bioexcel.eu/u/Nainsybaghel)\
**Post date:** [September 28, 2026, 9:50am UTC](https://gromacs.bioexcel.eu/t/addition-of-amber-ol3-force-field-in-gromacs/13726/3 "2026-09-28T09:50:00Z")

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Thankyou @jindrich.lnenicka