Error "invalid pair style" in a 2-atoms type model

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1

Hello,

I am trying to build a model consisting in a fluid between 2 layers of copper but lammps gives me an error I don’t know how to solve. Apparently the pair style to set the potentials is incorrect, but I don’t know how to tell lammps I want to use an eam potential for copper and a lj potential for the fluid (and the interaction between the fluid an the copper). I copy part of the script:
"
echo both
dimension 3
boundary p s p

atom_style atomic
neighbor 2.0 bin
neigh_modify delay 1
units metal

create geometry

region total block 0 108.45 0 216.9 0 108.45 units box

create_box 2 total

region fluid block 0 108.45 72.3 144.6 0 108.45 units box

lattice fcc 3.61500000000000021316 orient x 1 0 0 orient y 0 1 0 orient z 0 0 1
region copper-down block 0 108.45 0 72.3 0 108.45 units box

lattice fcc 3.61500000000000021316 orient x 1 0 0 orient y 0 1 0 orient z 0 0 1
region copper-up block 0 108.45 144.6 216.9 0 108.45 units box

create atoms and set potentials

create_atoms 1 region copper-down
mass 1 1.0

create_atoms 2 random 10000 482748 fluid
mass 2 1.0

create_atoms 1 region copper-up
mass 1 1.0

pair_style hybrid eam/alloy lj/cut/6.17
pair_coeff 1 1 Cu_mishin1.eam.alloy Cu
pair_coeff 1* 2 1.0 1.0
"

Thank you in advance for your help.

2

roger,

[...]

pair_style hybrid eam/alloy lj/cut 6.17

the problem is in these two lines:

pair_coeff 1 1 Cu_mishin1.eam.alloy Cu
pair_coeff 1* 2 1.0 1.0

manybody potentials (with the exception of eam which supports
only one type of atom) always have to use pair_coeff * *

pair_coeff * * eam/alloy Cu_mishin1.eam.alloy Cu NULL

and the designated potential has to be identified.

pair_coeff 1* 2 lj/cut 1.0 1.0

the documentation page for pair_style hybrid gives examples.
you only have to follow them.

axel.