Dear lammps users;
I want to simulate adsorption of a HCN molecule on a graphene substrate.
In HCN molecule, C atom is type 1; H atom is type 2 and N atom is type 3.
In graphene, C atoms are type 1. I want to use 2 many-body potentials
together, in an overlapping manner. I want to use reax/c potential for HCN
atoms and HCN/graphene interactions, and REBO for C/C in graphene
interactions.
you cannot do this. neither REBO nor Reax are pairwise additive
potentials, thus they can only be used with pair style hybrid, when they
describe *all* permutations of multiples of atoms of the associated atom
types. i.e. if you describe type 1 and type 2 with one of them, you have to
include *all* permutations of those types for pairs, triples, and
quadruples with the same manybody potential.
why not use ReaxFF for the whole system?
now I want to know how will be the pair style and pair coeff commands?
I used something like this but it has an error : "Pair coeff for hybrid
has invalid style"
here is the input and data file, other require files also is attached.
-------------------------------------------
units real
atom_style charge
read_data data.HCN
read_data data.graphene add append offset 1 0 0 0 0
pair_style hybrid reax/c NULL rebo
pair_coeff 1 3 ffield.reax C H N
pair_coeff 2 2 rebo CH.airebo NULL C
both pair_coeff lines are incorrect. for manybody potentials, you *must*
use the all-encompassing pair_coeff * * for reasons outlined above. this
is also explained in the manual.
axel.
neighbor 2 bin
neigh_modify every 10 delay 0 check no
fix 1 all nve
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
thermo 100
timestep 0.25
dump 1 all atom 30 dump.lammpstrj
run 300000
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.