Gromacs documentation on water solvation states:
"When using any 3-point model (e.g. [SPC], [SPC/E]or [TIP3P] ) you should specify
-cs spc216.gro which will take this file from the
gromacs/share/top directory. Other water models (e.g. [TIP4P] and [TIP5P] ) are available as well. "
When using TIP4P, what is the command that should be used rather than -cs spc216.gro ?