151 lines
4.7 KiB
ReStructuredText
151 lines
4.7 KiB
ReStructuredText
.. index:: pair_style rebomos
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.. index:: pair_style rebomos/omp
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pair_style rebomos command
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==========================
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Accelerator Variants: *rebomos/omp*
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Syntax
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""""""
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.. code-block:: LAMMPS
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pair_style rebomos
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* rebomos = name of this pair style
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Examples
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""""""""
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.. code-block:: LAMMPS
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pair_style rebomos
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pair_coeff * * ../potentials/MoS.rebomos Mo S
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Example input scripts available: examples/threebody/
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Description
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"""""""""""
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.. versionadded:: 17Apr2024
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The *rebomos* pair style computes the interactions between molybdenum
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and sulfur atoms :ref:`(Stewart) <Stewart>` utilizing an adaptive
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interatomic reactive empirical bond order potential that is similar in
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form to the AIREBO potential :ref:`(Stuart) <Stuart2>`. The potential
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is based on an earlier parameterizations for :math:`\text{MoS}_2`
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developed by :ref:`(Liang) <Liang>`.
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The REBOMoS potential consists of two terms:
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.. math::
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E & = \frac{1}{2} \sum_i \sum_{j \neq i}
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\left[ E^{\text{REBO}}_{ij} + E^{\text{LJ}}_{ij} \right] \\
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The :math:`E^{\text{REBO}}` term describes the covalently bonded
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interactions between Mo and S atoms while the :math:`E^{\text{LJ}}` term
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describes longer range dispersion forces between layers. A cubic spline
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function is applied to smoothly switch between covalent bonding at short
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distances to dispersion interactions at longer distances. This allows
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the model to capture bond formation and breaking events which may occur
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between adjacent MoS2 layers, edges, defects, and more.
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----------
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Only a single pair_coeff command is used with the *rebomos* pair style
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which specifies an REBOMoS potential file with parameters for Mo and S.
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These are mapped to LAMMPS atom types by specifying N additional
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arguments after the filename in the pair_coeff command, where N is the
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number of LAMMPS atom types:
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* filename
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* :math:`N` element names = mapping of REBOMoS elements to atom types
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See the :doc:`pair_coeff <pair_coeff>` 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 three atom types and you want
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the first two to be Mo, and the third to be S, you would use the following
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pair_coeff command:
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.. code-block:: LAMMPS
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pair_coeff * * MoS.rebomos Mo Mo S
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The first 2 arguments must be \* \* so as to span all LAMMPS atom types.
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The first two Mo arguments map LAMMPS atom types 1 and 2 to the Mo
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element in the REBOMoS file. The final S argument maps LAMMPS atom type
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3 to the S element in the REBOMoS file. If a mapping value is specified
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as NULL, the mapping is not performed. This can be used when a
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*rebomos* potential is used as part of the *hybrid* pair style. The
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NULL values are placeholders for atom types that will be used with other
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potentials.
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----------
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.. include:: accel_styles.rst
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----------
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Mixing, shift, table, tail correction, restart, rRESPA info
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"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
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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 their information to :doc:`binary restart
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files <restart>`, since it is stored in potential files. Thus, you need
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to re-specify the pair_style and pair_coeff commands in an input script
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that reads a restart file.
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This pair styles 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 style is part of the MANYBODY package. It is only enabled if
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LAMMPS was built with that package. See the :doc:`Build package
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<Build_package>` page for more info.
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These pair potentials require the :doc:`newton <newton>` setting to be
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"on" for pair interactions.
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The MoS.rebomos 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 *rebomos* pair style with any LAMMPS units setting, but you would
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need to create your own REBOMoS potential file with coefficients listed
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in the appropriate units.
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The pair style provided here **only** supports potential files parameterized
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for the elements molybdenum and sulfur (designated with "Mo" and "S" in the
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*pair_coeff* command. Using potential files for other elements will trigger
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an error.
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Related commands
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""""""""""""""""
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:doc:`pair_coeff <pair_coeff>`, :doc:`pair style rebo <pair_airebo>`
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Default
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"""""""
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none
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----------
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.. _Stewart:
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**(Steward)** Stewart, Spearot, Modelling Simul. Mater. Sci. Eng. 21, 045003, (2013).
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.. _Stuart2:
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**(Stuart)** Stuart, Tutein, Harrison, J Chem Phys, 112, 6472-6486, (2000).
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.. _Liang:
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**(Liang)** Liang, Phillpot, Sinnott Phys. Rev. B79 245110, (2009), Erratum: Phys. Rev. B85 199903(E), (2012)
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