114 lines
3.5 KiB
ReStructuredText
114 lines
3.5 KiB
ReStructuredText
.. index:: pair_style coul/shield
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pair_style coul/shield command
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==============================
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Syntax
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""""""
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.. code-block:: LAMMPS
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pair_style coul/shield cutoff tap_flag
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* cutoff = global cutoff (distance units)
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* tap_flag = 0/1 to turn off/on the taper function
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Examples
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""""""""
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.. code-block:: LAMMPS
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pair_style coul/shield 16.0 1
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pair_coeff 1 2 0.70
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Description
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"""""""""""
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Style *coul/shield* computes a Coulomb interaction for boron and
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nitrogen atoms located in different layers of hexagonal boron
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nitride. This potential is designed be used in combination with
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the pair style :doc:`ilp/graphene/hbn <pair_ilp_graphene_hbn>`
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.. note::
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This potential is intended for electrostatic interactions between
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two different layers of hexagonal boron nitride. Therefore, to avoid
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interaction within the same layers, each layer should have a separate
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molecule id and is recommended to use the "full" atom style, so that
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charge and molecule ID information is included.
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.. math::
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E = & \frac{1}{2} \sum_i \sum_{j \neq i} V_{ij} \\
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V_{ij} = & \mathrm{Tap}(r_{ij})\frac{\kappa q_i q_j}{\sqrt[3]{r_{ij}^3+(1/\lambda_{ij})^3}}\\
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\mathrm{Tap}(r_{ij}) = & 20\left ( \frac{r_{ij}}{R_{cut}} \right )^7 -
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70\left ( \frac{r_{ij}}{R_{cut}} \right )^6 +
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84\left ( \frac{r_{ij}}{R_{cut}} \right )^5 -
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35\left ( \frac{r_{ij}}{R_{cut}} \right )^4 + 1
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Where Tap(:math:`r_{ij}`) is the taper function which provides a continuous cutoff
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(up to third derivative) for inter-atomic separations larger than :math:`r_c`
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:ref:`(Leven1) <Leven3>`, :ref:`(Leven2) <Leven4>` and :ref:`(Maaravi) <Maaravi1>`.
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Here :math:`\lambda` is the shielding parameter that
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eliminates the short-range singularity of the classical mono-polar
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electrostatic interaction expression :ref:`(Maaravi) <Maaravi1>`.
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The shielding parameter :math:`\lambda` (1/distance units) must be defined for
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each pair of atom types via the :doc:`pair_coeff <pair_coeff>` command as
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in the example above, or in the data file or restart files read by the
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:doc:`read_data <read_data>` or :doc:`read_restart <read_restart>` commands:
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The global cutoff (:math:`r_c`) specified in the pair_style command is used.
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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 parameter mixing. Coefficients must
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be given explicitly for each type of particle pairs.
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The :doc:`pair_modify <pair_modify>` *table* option is not relevant
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for this pair style.
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This pair style does not support the :doc:`pair_modify <pair_modify>`
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*tail* option for adding long-range tail corrections to energy and
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pressure.
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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 style is part of the INTERLAYER package. It is only enabled
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if 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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Related commands
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""""""""""""""""
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:doc:`pair_coeff <pair_coeff>`
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:doc:`pair_style ilp/graphene/hbn <pair_ilp_graphene_hbn>`
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Default
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"""""""
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tap_flag = 1
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----------
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.. _Leven3:
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**(Leven1)** I. Leven, I. Azuri, L. Kronik and O. Hod, J. Chem. Phys. 140, 104106 (2014).
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.. _Leven4:
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**(Leven2)** I. Leven et al, J. Chem.Theory Comput. 12, 2896-905 (2016).
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.. _Maaravi1:
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**(Maaravi)** T. Maaravi et al, J. Phys. Chem. C 121, 22826-22835 (2017).
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