LJ with cutoff Coulomb for TIP4P water with a soft core

May I ask why would you want t use the tip4p/cut? It will not describe Coulomb interactions correctly and these are important for water. With today’s computers and fast long range solvers (PPPM) I don’t see a valid reason not to use long-range corrections (in many situations they don’t add that much overhead when compared to the CPU time spend on pair styles). That’s why I never bothered to propose a tip4p/cut/soft.

I recommend you test your version by plotting the pairwise energy/forces between 2 TIP4P water molecules and by running a test with soft and normal potentials.