Adding Lennard Jones Cross Terms to AMBER ff in GROMACS

User discussions
1

GROMACS version: 2022.4
GROMACS modification: Yes/No

Hello,

I would like to inquire if it is possible to include a [ nonbond_params ] section for custom cross Lennard-Jones terms (I take it that is what it is for) in the ffnonbonded.itp from one of the amber ff distributed natively with the gromacs as is available in the gromos one’s, in a way that the engine uses those instead of computing using the LB combination rules. If yes, then what changes (if any) need to be made the main forcefield.itp. Any guidance is greatly appreciated.

2

You can add LJ parameters for any pair of atom types, overriding the combination rule in a [ nonbond_params ] section. If this results in a reasonable force field is another question.

I don’t understand what GROMOS has to do with this.

3

Thank you.