Update docs: angle_charmm

\documentclass[12pt]{article}

\begin{document}

$$ 

  E = K (\theta - \theta_0)^2 + K_{UB} (r - r_{UB})^2 

$$

\end{document}

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.. index:: angle\_style charmm

.. index:: angle_style charmm

angle\_style charmm command

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

angle_style charmm command

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

angle\_style charmm/intel command

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

angle_style charmm/intel command

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

angle\_style charmm/kk command

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

angle_style charmm/kk command

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

angle\_style charmm/omp command

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

angle_style charmm/omp command

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

Syntax

""""""

.. parsed-literal::

.. code-block:: LAMMPS

   angle_style charmm

""""""""

.. parsed-literal::

.. code-block:: LAMMPS

   angle_style charmm

   angle_coeff 1 300.0 107.0 50.0 3.0

The *charmm* angle style uses the potential

.. image:: Eqs/angle_charmm.jpg

   :align: center

.. math::

   E = K (\theta - \theta_0)^2 + K_{ub} (r - r_{ub})^2

with an additional Urey\_Bradley term based on the distance *r* between

the 1st and 3rd atoms in the angle.  K, theta0, Kub, and Rub are

coefficients defined for each angle type.

with an additional Urey\_Bradley term based on the distance :math:`r` between

the 1st and 3rd atoms in the angle.  :math:`K`, :math:`\theta_0`,

:math:`K_{ub}`, and :math:`R_{ub}` are coefficients defined for each angle

type.

See :ref:`(MacKerell) <angle-MacKerell>` for a description of the CHARMM force

field.

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

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

* K (energy/radian\^2)

* theta0 (degrees)

* K\_ub (energy/distance\^2)

* r\_ub (distance)

* :math:`K` (energy/radian\^2)

* :math:`\theta_0` (degrees)

* :math:`K_{ub}` (energy/distance\^2)

* :math:`r_{ub}` (distance)

Theta0 is specified in degrees, but LAMMPS converts it to radians

internally; hence the units of K are in energy/radian\^2.

:math:`\theta_0` is specified in degrees, but LAMMPS converts it to radians

internally; hence the units of :math:`K` are in energy/radian\^2.

----------

**(MacKerell)** MacKerell, Bashford, Bellott, Dunbrack, Evanseck, Field,

Fischer, Gao, Guo, Ha, et al, J Phys Chem, 102, 3586 (1998).

.. _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

angle_style charmm command :h3

angle_style charmm/intel command :h3

angle_style charmm/kk command :h3

angle_style charmm/omp command :h3

[Syntax:]

angle_style charmm :pre

[Examples:]

angle_style charmm

angle_coeff 1 300.0 107.0 50.0 3.0 :pre

[Description:]

The {charmm} angle style uses the potential

:c,image(Eqs/angle_charmm.jpg)

with an additional Urey_Bradley term based on the distance {r} between

the 1st and 3rd atoms in the angle.  K, theta0, Kub, and Rub are

coefficients defined for each angle type.

See "(MacKerell)"_#angle-MacKerell for a description of the CHARMM force

field.

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

"angle_coeff"_angle_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:

K (energy/radian^2)

theta0 (degrees)

K_ub (energy/distance^2)

r_ub (distance) :ul

Theta0 is specified in degrees, but LAMMPS converts it to radians

internally; hence the units of K are in energy/radian^2.

: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 "Speed packages"_Speed_packages.html doc page for more

instructions on how to use the accelerated styles effectively.

:line

[Restrictions:]

This angle 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:]

"angle_coeff"_angle_coeff.html

[Default:] none

:line

:link(angle-MacKerell)

[(MacKerell)] MacKerell, Bashford, Bellott, Dunbrack, Evanseck, Field,

Fischer, Gao, Guo, Ha, et al, J Phys Chem, 102, 3586 (1998).