forked from lijiext/lammps
136 lines
4.3 KiB
Plaintext
136 lines
4.3 KiB
Plaintext
.. index:: pair_style kim
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pair_style kim command
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======================
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Syntax
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""""""
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.. parsed-literal::
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pair_style kim virialmode model printflag
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* virialmode = KIMvirial or LAMMPSvirial
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* model = name of KIM model (potential)
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* printflag = 1/0 do or do not print KIM descriptor file, optional
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Examples
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""""""""
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.. parsed-literal::
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pair_style kim KIMvirial model_Ar_P_Morse
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pair_coeff * * Ar Ar
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.. parsed-literal::
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pair_style kim KIMvirial model_Ar_P_Morse 1
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pair_coeff * * Ar Ar
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Description
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"""""""""""
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This pair style is a wrapper on the `Knowledge Base for Interatomic Models (KIM) <https://openkim.org>`_ repository of interatomic potentials,
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so that they can be used by LAMMPS scripts.
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In KIM lingo, a potential is a "model" and a model contains both the
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analytic formulas that define the potential as well as the parameters
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needed to run it for one or more materials, including coefficients and
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cutoffs.
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The argument *virialmode* determines how the global virial is
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calculated. If *KIMvirial* is specified, the KIM model performs the
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global virial calculation (if it knows how). If *LAMMPSvirial* is
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specified, LAMMPS computes the global virial using its fdotr mechanism.
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The argument *model* is the name of the KIM model for a specific
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potential as KIM defines it. In principle, LAMMPS can invoke any KIM
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model. You should get an error or warning message from either LAMMPS
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or KIM if there is an incompatibility.
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The argument *printflag* is optional. If it is set to a non-zero
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value then a KIM dsecriptor file is printed when KIM is invoked. This
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can be useful for debugging. The default is to not print this file.
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Only a single pair_coeff command is used with the *kim* style which
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specifies the mapping of LAMMPS atom types to KIM elements. This is
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done by specifying N additional arguments after the * * in the
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pair_coeff command, where N is the number of LAMMPS atom types:
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* N element names = mapping of KIM elements to atom types
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As an example, imagine the KIM model supports Si and C atoms. If your
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LAMMPS simulation has 4 atom types and you want the 1st 3 to be Si,
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and the 4th to be C, you would use the following pair_coeff command:
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.. parsed-literal::
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pair_coeff * * Si Si Si C
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The 1st 2 arguments must be * * so as to span all LAMMPS atom types.
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The first three Si arguments map LAMMPS atom types 1,2,3 to Si as
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defined within KIM. The final C argument maps LAMMPS atom type 4 to C
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as defined within KIM. If a mapping value is specified as NULL, the
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mapping is not performed. This can only be used when a *kim*
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potential is used as part of the *hybrid* pair style. The NULL values
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are placeholders for atom types that will be used with other
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potentials.
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----------
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In addition to the usual LAMMPS error messages, the KIM library itself
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may generate errors, which should be printed to the screen. In this
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case it is also useful to check the kim.log file for additional error
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information. This file kim.log should be generated in the same
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directory where LAMMPS is running.
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To download, build, and install the KIM library on your system, see
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the lib/kim/README file. Once you have done this and built LAMMPS
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with the KIM package installed you can run the example input scripts
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in examples/kim.
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----------
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**Mixing, shift, table, tail correction, restart, rRESPA info**\ :
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This pair style does not support the :doc:`pair_modify <pair_modify>`
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mix, shift, table, and tail options.
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This pair style does not write its information to :doc:`binary restart files <restart>`, since KIM stores the potential parameters.
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Thus, you need to re-specify the pair_style and pair_coeff commands in
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an input script that reads a restart file.
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This pair style can only be used via the *pair* keyword of the
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:doc:`run_style respa <run_style>` command. It does not support the
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*inner*\ , *middle*\ , *outer* keywords.
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----------
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Restrictions
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""""""""""""
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This pair style is part of the KIM package. It is only enabled if
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LAMMPS was built with that package. See the :ref:`Making LAMMPS <start_3>` section for more info.
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This current version of pair_style kim is compatible with the
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kim-api package version 1.6.0 and higher.
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Related commands
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""""""""""""""""
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:doc:`pair_coeff <pair_coeff>`
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**Default:** none
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.. _lws: http://lammps.sandia.gov
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.. _ld: Manual.html
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.. _lc: Section_commands.html#comm
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