Turn off calculation of vdW interaction for hydrogen atoms

Hi everybody

I want to simulate a huge system mostly composed of SPC water molecules. As this force field set hydrogen vdW parameters to zero, is there any way to turn off the calculation of vdw interaction between water hydrogens any other particles?


Are you asking an optimization Q, meaning you
want to not compute some vdW terms with zeroes?
If so, I think you would have to edit the pair lj/cut/coul/long.cpp
file to check and skip those terms. Since it also
doing the non-zero Coulombic interactions it can’t
skip the H interactions entirely. I don’t think doing
that check would speed things up dramatically.