Incorrect args for pair coefficients

LAMMPS LAMMPS Beginners
1

Dear users,

I am stuck in using meam potential.
As I understand the usage, I put meam arguments like this,
pair_coeff * * library.meam Ni V NiV.meam Ni V
asterisks to span all types of atoms, exporting elements, parameters, and the target types with names.
But I kept getting incorrect args error in this line.
Can you give any advices ??

Thank you!!

units metal
dimension 3
boundary p p s
atom_style atomic
variable latparam1 equal 3.52

variable xdim equal ${latparam1}*sqrt(6)/2*15
variable ydim equal ${latparam1}*sqrt(2)/2*15
variable b equal ${latparam1}*sqrt(6)/6

lattice fcc ${latparam1}
region 1 block 0 ${xdim} 0 ${ydim} 0 30
region 2 block 0 ${xdim} 0 ${ydim} 30 60
region 3 block 0 ${xdim} 0 ${ydim} 0 5
region 4 block 0 ${xdim} 0 ${ydim} 55 60
region 5 block 0 ${xdim} 0 ${ydim} 5 55

region whole block 0 ${xdim} 0 ${ydim} 0 200 units box
create_box 6 whole
lattice fcc ${latparam1} orient x 1 1 2 orient y -1 1 0 orient z -1 -1 1
create_atoms 1 region 1
lattice fcc ${latparam1} orient x 1 1 2 orient y -1 1 0 orient z -1 -1 1
create_atoms 1 region 2
set type 1 type/fraction 2 0.5 11654

pair_style meam
pair_coeff * * library.meam Ni V NiV.meam Ni V
2

Please study the documentation of the pair_coeff command and the pair_style meam command for detailed discussions.

In summary, the pair_coeff command gives an error because you do not have a mapping of elements taken from the potential to the atom types in LAMMPS. You are only mapping Ni to atom type 1 and V to atom type 2 (rightmost two arguments), but you have 6 atom types, so LAMMPS is looking for 4 more arguments to the pair_coeff command.

3

Dear akohlmey,

I appreciate a lot !!
I fixed that by changing create_box with 2 types of atoms.
I thought that was because of pair_coeff code,
but the problem was that I didn’t fully distinguish index and types to be defined.
Now it worked as I intended.
Thanks to you.