GROMACS version: 2020.3
GROMACS modification: No
I am attempting to restrain the orientation of a small molecule using three position restraints that span the ligand and to scale these restraints from 0-800 kJ mol-1 nm-2 using restraint-lambdas in order to compute the free energy of coupling the restraints.
After first using [ position_restraints ] in the ligand topology and seeing that restraint-lambdas “only the restraint interactions: dihedral restraints, and the pull code restraints are controlled with this component of the lambda vector,” I opted to define three pull groups between each of the ligand atoms and a super-imposed, frozen dummy atom.
However, the restraint-lambdas still have no effect on de-coupling these restraints.
I saw a post recently: https://gromacs.bioexcel.eu/t/restraints-with-fep/2109 that seems to be attempting a similar protocol, but they also had no success implementing restraint-lambdas.
Am I missing a crucial mdp parameter or topology definition?