[lammps-users] pair_style hybrid/overlay


I tried to use the following script:

pair_style hybrid/overlay coul/long 20.5 table linear 1000

pair_coeff * * coul/long
pair_coeff 1 1 table U_col_col U_col_col
pair_coeff 2 2 table U_ion_ion U_ion_ion
pair_coeff 1 2 table U_col_ion U_col_ion

pair_modify shift yes
kspace_style pppm 0.0005
kspace_modify slab 3.0 ## my system is 2D

LAMMPS gave me the following error message:
Coulomb cutoffs of pair hybrid sub-styles do not match

I have no clue why I got this error message, could someone tell me where is the mistake? Thank you in advance!


From doc/Section_errors.html

Coulomb cutoffs of pair hybrid sub-styles do not match

If using a Kspace solver, all Coulomb cutoffs of long pair styles must
be the same.

I'm guessing your tabled potentials don't have a cutoff of 20.5


Hi Steve,

Thank you for your reply. You are right that my tabulated potentials don’t have a cutoff of 20.5. However, the tabulated potentials are for VDWs interactions, not electrostatic interactions. Why does Kspace solver care about the cutoffs of VDWs interactions? If the tabulated potential includes electrostatic interaction, I guess we can’t use Kspace solver. Therefore I can’t see any relationship between Kspace solver and the cutoffs of VDWs interactions. Is there anyway to work around? Or I have to use coul/cut if tabulated potentials are used?

All the best!


There needs to be some way for a table potential to identify itself as
Coulombic or not. Right now it is assuming they all are, if you are
using PPPM, which isn't what you want. If you comment out the
last line in pair_table.cpp (return &tables[0].cut) and replace
it with (return NULL) then I think it will work for your problem.