How to constrain the centre of mass for a group of atoms

User discussions
,
1

GROMACS version: 2021
GROMACS modification: Yes
Dear Users,
Is it possible to constrain the centre of mass a of a particular group of atoms in gromacs without freezing it. so, that the molecules doesn’t get drifted and remain at a particular position in the simulation box.

Thanks
Dev

2

yes in the parameters file *.mdp you can define the group that you want to restrain it (make sure to enable this option) , and check your force filed file to find the constraint commands for each type of atoms you have in your system

3

Can you please elaborate which option you are talking about in the mdp file?..and which constraint command you are talking about? a sample of how the line looks will help a lot.

Thanks,
Dev

4

Hi Dev
Read this, (Preprocessing) section
http://bpg.utoledo.edu/gromacs/online/mdp_opt.html

5

You can apply individual atom-based restraints but GROMACS does not have the ability to restrain COM of selected atoms.