AIREBO, TIP4P, Hybrid potentials, error

Dear there,

I am trying to use the hybrid potential to describe the interactions between Water (TIP4P) and Graphite (AIREBO). The graphite is edge-saturated by hydrogen atoms.

Here is what I am using in the input file:

Hybrid

TIP4P for H2O - H2O

AIREBO for Graphite

LJ for H2O - Graphite

pair_style hybrid airebo 2.5 1 1 lj/cut/coul/long/tip4p 2 3 1 1 0.1546 14.0 lj/charmm/coul/long/opt 16.0 18.0 18.0

Graphite

pair_coeff * * airebo CH.airebo C NULL NULL H

H2O - Graphite

pair_coeff 1 2 lj/charmm/coul/long/opt 0.0929780274 3.283
pair_coeff 1 3 lj/charmm/coul/long/opt 0.0000000000 1.700
pair_coeff 4 2 lj/charmm/coul/long/opt 0.0000000000 1.579
pair_coeff 4 3 lj/charmm/coul/long/opt 0.0000000000 0.000

H2O - H2O

pair_coeff 2 2 lj/cut/coul/long/tip4p 0.1852573718 3.1589
pair_coeff 2 3 lj/cut/coul/long/tip4p 0.0000000000 1.5795
pair_coeff 3 3 lj/cut/coul/long/tip4p 0.0000000000 0.0000

I got the message below when it comes to H2O-Graphite interaction:

H2O - Graphite

pair_coeff 1 2 lj/charmm/coul/long/opt 0.0929780274 3.283
pair_coeff 1 3 lj/charmm/coul/long/opt 0.0000000000 1.700
pair_coeff 4 2 lj/charmm/coul/long/opt 0.0000000000 1.579
ERROR: Incorrect args for pair coefficients

I have not put the parameters into the correct values, but something might be wrong with the format. I guess it is related with the H atom of AIREBO.

Any comment will be greatly appreciated.

Liangliang
from CHE, NCSU.

Dear there,
I am trying to use the hybrid potential to describe the interactions between
Water (TIP4P) and Graphite (AIREBO). The graphite is edge-saturated by
hydrogen atoms.
Here is what I am using in the input file:
# Hybrid
# TIP4P for H2O - H2O
# AIREBO for Graphite
# LJ for H2O - Graphite
pair_style hybrid airebo 2.5 1 1 lj/cut/coul/long/tip4p 2 3 1 1 0.1546 14.0
lj/charmm/coul/long/opt 16.0 18.0 18.0
# Graphite
pair_coeff * * airebo CH.airebo C NULL NULL H
# H2O - Graphite
pair_coeff 1 2 lj/charmm/coul/long/opt 0.0929780274 3.283
pair_coeff 1 3 lj/charmm/coul/long/opt 0.0000000000 1.700
pair_coeff 4 2 lj/charmm/coul/long/opt 0.0000000000 1.579
pair_coeff 4 3 lj/charmm/coul/long/opt 0.0000000000 0.000
# H2O - H2O
pair_coeff 2 2 lj/cut/coul/long/tip4p 0.1852573718 3.1589
pair_coeff 2 3 lj/cut/coul/long/tip4p 0.0000000000 1.5795
pair_coeff 3 3 lj/cut/coul/long/tip4p 0.0000000000 0.0000

I got the message below when it comes to H2O-Graphite interaction:
# H2O - Graphite
pair_coeff 1 2 lj/charmm/coul/long/opt 0.0929780274 3.283
pair_coeff 1 3 lj/charmm/coul/long/opt 0.0000000000 1.700
pair_coeff 4 2 lj/charmm/coul/long/opt 0.0000000000 1.579
ERROR: Incorrect args for pair coefficients
I have not put the parameters into the correct values, but something might
be wrong with the format. I guess it is related with the H atom of AIREBO.

no. check out the pair_coeff documentation.
you *must* not have pair_coeff 4 2 ...
the first number has to be lower or equal than the second.

axel.

Thanks a lot, Alex.

It is working now after I change the numbering order.

Liangliang
from CHE, NCSU