Update docs: bond_morse

\documentclass[12pt]{article}

\begin{document}

$$

%   E = D \left[ 1 - \exp \left( -\alpha (r - r_0) \right) \right]^2 

   E = D \left[ 1 - e^{-\alpha (r - r_0)} \right]^2 

$$

\end{document}

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.. index:: bond\_style morse

.. index:: bond_style morse

bond\_style morse command

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

bond_style morse command

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

bond\_style morse/omp command

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

bond_style morse/omp command

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

Syntax

""""""

.. parsed-literal::

.. code-block:: LAMMPS

   bond_style morse

""""""""

.. parsed-literal::

.. code-block:: LAMMPS

   bond_style morse

   bond_coeff 5 1.0 2.0 1.2

The *morse* bond style uses the potential

.. image:: Eqs/bond_morse.jpg

   :align: center

.. math::

where r0 is the equilibrium bond distance, alpha is a stiffness

parameter, and D determines the depth of the potential well.

   E = D \left[ 1 - e^{-\alpha (r - r_0)} \right]^2

where :math:`r_0` is the equilibrium bond distance, :math:`\alpha` is a stiffness

parameter, and :math:`D` determines the depth of the potential well.

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:

* D (energy)

* alpha (inverse distance)

* r0 (distance)

* :math:`D` (energy)

* :math:`\alpha` (inverse distance)

* :math:`r_0` (distance)

----------

:doc:`bond\_coeff <bond_coeff>`, :doc:`delete\_bonds <delete_bonds>`

**Default:** none

.. _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 morse command :h3

bond_style morse/omp command :h3

[Syntax:]

bond_style morse :pre

[Examples:]

bond_style morse

bond_coeff 5 1.0 2.0 1.2 :pre

[Description:]

The {morse} bond style uses the potential

:c,image(Eqs/bond_morse.jpg)

where r0 is the equilibrium bond distance, alpha is a stiffness

parameter, and D determines the depth of the potential well.

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:

D (energy)

alpha (inverse distance)

r0 (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