Hello,
thank you for getting back to me so quickly!
I appreciate that CHARMM was originally parametrised with TIP3P “in mind”, but I am rather confident in saying that there are quite a few GROMACS users out there that are using TIP5P and even more so TIP4Pas well - particularly in light of the fact that these water models seem to be behaving quite accurately in conjunction with CHARMM (even though the latter was not parametrised with the former in mind).
I also appreciate that, in most cases, users would not go through the pdb2gmx route to work with TIP4P.
It’s just that some of the TIP4P parameters were wrong in the charmm36-jul2021.ff already - it’s only a few lines, and it’s not a great effort for a user to check every release manually (as you can tell, I always do that in any case…) but it’d be great to fix them nonetheless!
Thank you for your help, massively appreciated indeed.
Best wishes,
Gabriele