forked from lijiext/lammps
115 lines
3.4 KiB
Plaintext
115 lines
3.4 KiB
Plaintext
.. index:: pair_style lcbop
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pair_style lcbop 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 lcbop
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Examples
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""""""""
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.. parsed-literal::
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pair_style lcbop
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pair_coeff * * ../potentials/C.lcbop C
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Description
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"""""""""""
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The *lcbop* pair style computes the long-range bond-order potential
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for carbon (LCBOP) of :ref:`(Los and Fasolino) <Los>`. See section II in
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that paper for the analytic equations associated with the potential.
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Only a single pair_coeff command is used with the *lcbop* style which
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specifies an LCBOP potential file with parameters for specific
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elements. These are mapped to LAMMPS atom types by specifying N
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additional arguments after the filename in the pair_coeff command,
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where N is the number of LAMMPS atom types:
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* filename
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* N element names = mapping of LCBOP elements to atom types
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See the :doc:`pair_coeff <pair_coeff>` doc page for alternate ways
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to specify the path for the potential file.
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As an example, if your LAMMPS simulation has 4 atom types and you want
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the 1st 3 to be C you would use the following pair_coeff command:
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.. parsed-literal::
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pair_coeff * * C.lcbop C C C NULL
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The 1st 2 arguments must be * * so as to span all LAMMPS atom types.
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The first C argument maps LAMMPS atom type 1 to the C element in the
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LCBOP file. If a mapping value is specified as NULL, the mapping is
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not performed. This can be used when a *lcbop* potential is used as
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part of the *hybrid* pair style. The NULL values are placeholders for
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atom types that will be used with other potentials.
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The parameters/coefficients for the LCBOP potential as applied to C
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are listed in the C.lcbop file to agree with the original :ref:`(Los and Fasolino) <Los>` paper. Thus the parameters are specific to this
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potential and the way it was fit, so modifying the file should be done
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carefully.
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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 it is stored in potential files. Thus, you
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need to re-specify the pair_style and pair_coeff commands in an input
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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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Restrictions
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""""""""""""
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This pair styles is part of the MANYBODY package. It is only enabled
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if LAMMPS was built with that package (which it is by default). See
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the :ref:`Making LAMMPS <start_3>` section for more info.
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This pair potential requires the :doc:`newton <newton>` setting to be
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"on" for pair interactions.
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The C.lcbop potential file provided with LAMMPS (see the potentials
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directory) is parameterized for metal :doc:`units <units>`. You can use
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the LCBOP potential with any LAMMPS units, but you would need to
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create your own LCBOP potential file with coefficients listed in the
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appropriate units if your simulation doesn't use "metal" units.
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Related commands
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""""""""""""""""
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:doc:`pair_airebo <pair_airebo>`, :doc:`pair_coeff <pair_coeff>`
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**Default:** none
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----------
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.. _Los:
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**(Los and Fasolino)** J. H. Los and A. Fasolino, Phys. Rev. B 68, 024107
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(2003).
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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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