share/top/amber99sb.ff/watermodels.dat

   1 tip3p    TIP3P     TIP 3-point, recommended
   2 tip4p    TIP4P     TIP 4-point
   3 tip4pew  TIP4P-Ew  TIP 4-point optimized with Ewald, recommended
   4 tip5p    TIP5P     TIP 5-point (see https://gitlab.com/gromacs/gromacs/-/issues/1348 for issues)
   5 spc      SPC       simple point charge
   6 spce     SPC/E     extended simple point charge