Update docs: bond_nonlinear

\documentclass[12pt]{article}

\begin{document}

$$

  E = \frac{\epsilon (r - r_0)^2}{ [ \lambda^2 - (r - r_0)^2 ]}

$$

\end{document}

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.. index:: bond\_style nonlinear

.. index:: bond_style nonlinear

bond\_style nonlinear command

=============================

bond_style nonlinear command

============================

bond\_style nonlinear/omp command

=================================

bond_style nonlinear/omp command

================================

Syntax

""""""

.. parsed-literal::

.. code-block:: LAMMPS

   bond_style nonlinear

""""""""

.. parsed-literal::

.. code-block:: LAMMPS

   bond_style nonlinear

   bond_coeff 2 100.0 1.1 1.4

The *nonlinear* bond style uses the potential

.. image:: Eqs/bond_nonlinear.jpg

   :align: center

.. math::

   E = \frac{\epsilon (r - r_0)^2}{ [ \lambda^2 - (r - r_0)^2 ]}

to define an anharmonic spring :ref:`(Rector) <Rector>` of equilibrium

length r0 and maximum extension lamda.

length :math:`r_0` and maximum extension lamda.

The following coefficients must be defined for each bond type via the

:doc:`bond\_coeff <bond_coeff>` command as in the example above, or in

the data file or restart files read by the :doc:`read\_data <read_data>`

or :doc:`read\_restart <read_restart>` commands:

* epsilon (energy)

* r0 (distance)

* lamda (distance)

* :math:`\epsilon` (energy)

* :math:`r_0` (distance)

* :math:`\lambda` (distance)

----------

**(Rector)** Rector, Van Swol, Henderson, Molecular Physics, 82, 1009 (1994).

.. _lws: http://lammps.sandia.gov

.. _ld: Manual.html

.. _lc: Commands_all.html

"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)

:link(ld,Manual.html)

:link(lc,Commands_all.html)

:line

bond_style nonlinear command :h3

bond_style nonlinear/omp command :h3

[Syntax:]

bond_style nonlinear :pre

[Examples:]

bond_style nonlinear

bond_coeff 2 100.0 1.1 1.4 :pre

[Description:]

The {nonlinear} bond style uses the potential

:c,image(Eqs/bond_nonlinear.jpg)

to define an anharmonic spring "(Rector)"_#Rector of equilibrium

length r0 and maximum extension lamda.

The following coefficients must be defined for each bond type via the

"bond_coeff"_bond_coeff.html command as in the example above, or in

the data file or restart files read by the "read_data"_read_data.html

or "read_restart"_read_restart.html commands:

epsilon (energy)

r0 (distance)

lamda (distance) :ul

:line

Styles with a {gpu}, {intel}, {kk}, {omp}, or {opt} suffix are

functionally the same as the corresponding style without the suffix.

They have been optimized to run faster, depending on your available

hardware, as discussed on the "Speed packages"_Speed_packages.html doc

page.  The accelerated styles take the same arguments and should

produce the same results, except for round-off and precision issues.

These accelerated styles are part of the GPU, USER-INTEL, KOKKOS,

USER-OMP and OPT packages, respectively.  They are only enabled if

LAMMPS was built with those packages.  See the "Build

package"_Build_package.html doc page for more info.

You can specify the accelerated styles explicitly in your input script

by including their suffix, or you can use the "-suffix command-line

switch"_Run_options.html when you invoke LAMMPS, or you can use the

"suffix"_suffix.html command in your input script.

See the "Speed packages"_Speed_packages.html doc page for more

instructions on how to use the accelerated styles effectively.

:line

[Restrictions:]

This bond style can only be used if LAMMPS was built with the MOLECULE

package.  See the "Build package"_Build_package.html doc page for more

info.

[Related commands:]

"bond_coeff"_bond_coeff.html, "delete_bonds"_delete_bonds.html

[Default:] none

:line

:link(Rector)

[(Rector)] Rector, Van Swol, Henderson, Molecular Physics, 82, 1009 (1994).