GROMACS version:2022.0
GROMACS modification: No
Dear All,
I am currently working on simulations involving Cu²⁺ (specifically CuCl2 in aqueous solution with a polymer) using the GAFF force field in GROMACS. However, I noticed that the ions.itp files provided with the AMBER force fields (e.g., amber99.ff/ions.itp) do not include parameters for the Cu²⁺ ion. While I found Lennard-Jones (LJ) parameters for copper in files such as ffnonbonded.itp and atomtypes.atp, I understand that these are intended for elemental (neutral) copper, and therefore not suitable for representing Cu²⁺.
Could anyone kindly advise on how to obtain appropriate parameters for the Cu²⁺ ion that are compatible with the GAFF force field and usable within GROMACS?
Thank you in advance for your support.