[EXTERNAL] Help lj/gromacs/coul/gromacs + pppm + respa + shake

Please reply to the list, not to me.

You can’t use lj/gromacs/coul/gromacs with Kspace. It has a damping term for the coulombic interaction that is not compatible with long-range electrostatics. See http://lammps.sandia.gov/doc/pair_gromacs.html. You could try using pair hybrid with lj/gromacs + coul/long though or code up your own lj/gromacs/coul/long pair style.