76 lines
1.4 KiB
ReStructuredText
76 lines
1.4 KiB
ReStructuredText
.. index:: bond_style class2
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.. index:: bond_style class2/omp
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.. index:: bond_style class2/kk
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bond_style class2 command
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=========================
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Accelerator Variants: *class2/omp*, *class2/kk*
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Syntax
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""""""
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.. code-block:: LAMMPS
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bond_style class2
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Examples
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""""""""
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.. code-block:: LAMMPS
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bond_style class2
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bond_coeff 1 1.0 100.0 80.0 80.0
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Description
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"""""""""""
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The *class2* bond style uses the potential
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.. math::
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E = K_2 (r - r_0)^2 + K_3 (r - r_0)^3 + K_4 (r - r_0)^4
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where :math:`r_0` is the equilibrium bond distance.
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See :ref:`(Sun) <bond-Sun>` for a description of the COMPASS class2 force field.
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The following coefficients must be defined for each bond type via the
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:doc:`bond_coeff <bond_coeff>` command as in the example above, or in
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the data file or restart files read by the :doc:`read_data <read_data>`
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or :doc:`read_restart <read_restart>` commands:
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* :math:`r_0` (distance)
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* :math:`K_2` (energy/distance\^2)
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* :math:`K_3` (energy/distance\^3)
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* :math:`K_4` (energy/distance\^4)
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----------
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.. include:: accel_styles.rst
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----------
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Restrictions
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""""""""""""
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This bond style can only be used if LAMMPS was built with the CLASS2
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package. See the :doc:`Build package <Build_package>` doc page for more
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info.
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Related commands
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""""""""""""""""
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:doc:`bond_coeff <bond_coeff>`, :doc:`delete_bonds <delete_bonds>`
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Default
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"""""""
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none
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----------
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.. _bond-Sun:
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**(Sun)** Sun, J Phys Chem B 102, 7338-7364 (1998).
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