[lammps-users] Problems with SW.

Hello, everyone

i try to run the simulation attached and lammps fail
with this message:
[email protected]...:~/lammps/pruebas/moleculaSW$
lmp_serial < in.zinc
LAMMPS (12 Feb 2007)
Scanning data file ...
  4 = max bonds/atom
Reading data file ...
  1 by 1 by 1 processor grid
  18 atoms
  16 bonds
Finding 1-2 1-3 1-4 neighbors ...
  4 = max # of 1-2 neighbors
  6 = max # of 1-3 neighbors
  12 = max # of 1-4 neighbors
  13 = max # of special neighbors
18 atoms in group bloque
ERROR: Incorrect args for pair coefficients

i check the pair_style format and i don't know if
error refer to the command pair_style or the file

please, someone can tell me the error.

thank for all.

data.zinc (1.26 KB)

GaAs.sw (358 Bytes)

in.zinc (684 Bytes)

Hi sin-nombre,

I think your problem is the parameter file: in the data file you defined two types, and then in the param you have only one line:

GaAs GaAs GaAs 1.409 0.210 1.794 27.0 1.0 -0.333333333333 8.513 0.782 4.0 0.0

Look at the cdte.sw for an example of a 2 component sw system. I never did mixtures so I do not know whether the program knows
that the first element is type 1 and the second type 2 or it has to be indicated somewhere else.


Your data file has 2 types of atoms (presumably Ga and As), but
your pair_coeff command says there are three types (all GaAs).

You want pair_coef * * GaAs.sw Ga As

then in your GaAs.sw file you need 8 entries for all the permutations
of Ga and As interacting in 3-body terms. This is all explained in the
doc pages.