[gmx-users] How to add a repulsive harmonic potential

[atsutoshi.okabe at takeda.com]

Dear all

To avoid ligand aggregation under higher concentration, I would like to introduce a weak repulsive potential term between the specific(e.g nitrogen) atoms of ligand molecules in the Protein/Ligand/Water system.
This potential set as below.
U(R) = K(R-R0)^2, if R<R0 (repulsive potential)
U(R) = 0, if R>R0

Could you tell me how to add the repulsive harmonic potential in MD simulation?

Bests,
Atsutoshi Okabe