Dear lammps users,
I want to simulate a CNT in SPC/E water using a hybrid pair style with reaxFF for CNT and lj/charmm/coul/long for the interactions between CNT and water molecules.
Since I have to define explicit bonds between O and H while reaxFF uses implicit bonds, is there any way to solve this contradictory?
P.S. In essence, I am using reaxFF for only Carbon atoms and LJ for other interactions but in practice when I run the simulation I get the “Fix qeq/reax CG convergence failed” error.
Dear lammps users,
I want to simulate a CNT in SPC/E water using a hybrid pair style with reaxFF for CNT and lj/charmm/coul/long for the interactions between CNT and water molecules.
Since I have to define explicit bonds between O and H while reaxFF uses implicit bonds, is there any way to solve this contradictory?
find a reaxff parameterization that can work for both the CNT and the water. what you have is a bad model, since neither reaxff does expect to be handling charge equlibration with neighboring non-QEQ charged atoms, not is the SPC/E water parameterized to be interacting with a polarizable model. …and then there is the question of how you can handle the interaction between CNT and water correctly, since there is no parameterization for a cross-reaxff and spc/e interaction. …and you have another inconsistency: long-range electrostatics. while reaxff does something equivalent to a wolf sum (so long-range interactions are approximated within the real-space interactions, you cannot partition the kspace handling for the two sets of interactions with coul/long, and the kspace calculation will go across all atoms in the first place, so those kspace interactions are double counted.
in short, there are inconsistencies all over the place, and thus you should look for a better way of representing your system.
axel.