73 lines
1.4 KiB
ReStructuredText
73 lines
1.4 KiB
ReStructuredText
.. index:: bond_style nonlinear
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.. index:: bond_style nonlinear/omp
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bond_style nonlinear command
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============================
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Accelerator Variants: *nonlinear/omp*
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Syntax
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""""""
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.. code-block:: LAMMPS
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bond_style nonlinear
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Examples
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""""""""
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.. code-block:: LAMMPS
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bond_style nonlinear
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bond_coeff 2 100.0 1.1 1.4
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Description
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"""""""""""
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The *nonlinear* bond style uses the potential
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.. math::
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E = \frac{\epsilon (r - r_0)^2}{ [ \lambda^2 - (r - r_0)^2 ]}
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to define an anharmonic spring :ref:`(Rector) <Rector>` of equilibrium
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length :math:`r_0` and maximum extension lamda.
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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:`\epsilon` (energy)
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* :math:`r_0` (distance)
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* :math:`\lambda` (distance)
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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 EXTRA-MOLECULE
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package. See the :doc:`Build package <Build_package>` 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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.. _Rector:
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**(Rector)** Rector, Van Swol, Henderson, Molecular Physics, 82, 1009 (1994).
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