[gmx-users] Inorganic ammonium sulphate with CHARMM force field

[gozde ergin]

Hi everybody,

I would like o run ammonium sulphate solution with CHARMM force field in GROMACS.
pdb2gmx is not working because the residue type is LIG.
I tried to use swissparam and paramchem website however both do not support the inorganic sulphate and ammonium explicitly.
Is there any other easy way to get the ammonium sulphate input parameters with CHARMM force field for Gromacs ?

Thanks in advance.