lammps/doc/pair_kim.txt

"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

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pair_style kim command :h3

[Syntax:]

pair_style kim model :pre

model = name of KIM model (potential)

[Examples:]

pair_style kim model_Ar_P_Morse
pair_coeff * * Ar Ar :pre

[Description:]

This pair style is a wrapper on the Knowledge Base for Interatomic
Models (KIM) repository of interatomic potentials, so that they can be
used by LAMMPS scripts.

In KIM lingo, a potential is a "model" and a model contains both the
analytic formulas that define the potential as well as the parameters
needed to run it for one or more materials, including coefficients and
cutoffs.

The argument {model} is the name of the model for a specific potential
as KIM defines it.  In principle, LAMMPS can invoke any KIM model.
You should get an error message from either LAMMPS or KIM if there is
an incompatibility.

Only a single pair_coeff command is used with the {kim} style which
specifies the mapping of LAMMPS atom types to KIM elements.  This is
done by specifying N additional arguments after the "* *" in the
pair_coeff command, where N is the number of LAMMPS atom types:

N element names = mapping of KIM elements to atom types :ul

As an example, imagine the KIM model supports Si and C atoms.  If your
LAMMPS simulation has 4 atoms types and you want the 1st 3 to be Si,
and the 4th to be C, you would use the following pair_coeff command:

pair_coeff * * Si Si Si C :pre

The 1st 2 arguments must be * * so as to span all LAMMPS atom types.
The first three Si arguments map LAMMPS atom types 1,2,3 to Si as
defined within KIM.  The final C argument maps LAMMPS atom type 4 to C
as defined within KIM.  If a mapping value is specified as NULL, the
mapping is not performed.  This can be used when a {kim} potential is
used as part of the {hybrid} pair style.  The NULL values are
placeholders for atom types that will be used with other potentials.

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Where to look for error messages

Some of the KIM models might fail to work with lammps. Check generated
kim.log file for error messages.

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How to build KIM

ENV variables

setenv KIM_MODELS_DIR `pwd`/MODELs/
setenv KIM_DIR `pwd`/
setenv KIM_DYNAMIC yes

It is required that OPENKIM directory with
needed file structure is installed (can be downloaded from openkim.org)
and needed environment variables are set:
KIM_DIR = path  openkim-api directory
KIM_DYNAMIC -- if dynamic linking is used during building (default --static) 
KIM_MODELS_DIR = path to kim models directory (default -- $KIM_DIR/MODELs)
See openkim-api/INSTALL for detailed instruction.

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[Mixing, shift, table, tail correction, restart, rRESPA info]:

This pair style does not support the "pair_modify"_pair_modify.html
mix, shift, table, and tail options.

This pair style does not write its information to "binary restart
files"_restart.html, since KIM stores the the potential parameters.
Thus, you need to re-specify the pair_style and pair_coeff commands in
an input script that reads a restart file.

This pair style can only be used via the {pair} keyword of the
"run_style respa"_run_style.html command.  It does not support the
{inner}, {middle}, {outer} keywords.

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[Restrictions:]

This pair style is part of the KIM package.  It is only enabled if
LAMMPS was built with that package.  See the "Making
LAMMPS"_Section_start.html#start_3 section for more info.

This pair style requires the "newton"_newton.html setting to be "off"
for pair interactions.

Currently this pair style only works with LAMMPS metal
"units"_units.html, since KIM models are written using
those units.

Only KIM models that are using NEIGH-PURE-H, NEIGH-PURE-F and
NEIGH-RVEC-F can be used with lammps. (see KIM documentation on NBC
methods)

[Related commands:]

"pair_coeff"_pair_coeff.html, "pair_style eam"_pair_eam.html

[Default:] none