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lammps/doc/src/dihedral_multi_harmonic.rst
2025-02-28 00:07:46 -07:00

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.. index:: dihedral_style multi/harmonic
.. index:: dihedral_style multi/harmonic/omp
dihedral_style multi/harmonic command
=====================================
Accelerator Variants: *multi/harmonic/kk*, *multi/harmonic/omp*
Syntax
""""""
.. code-block:: LAMMPS
dihedral_style multi/harmonic
Examples
""""""""
.. code-block:: LAMMPS
dihedral_style multi/harmonic
dihedral_coeff 1 20 20 20 20 20
Description
"""""""""""
The *multi/harmonic* dihedral style uses the potential
.. math::
E = \sum_{n=1,5} A_n \cos^{n-1}(\phi)
The following coefficients must be defined for each dihedral type via the
:doc:`dihedral_coeff <dihedral_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:
* :math:`A_1` (energy)
* :math:`A_2` (energy)
* :math:`A_3` (energy)
* :math:`A_4` (energy)
* :math:`A_5` (energy)
----------
.. include:: accel_styles.rst
----------
Restrictions
""""""""""""
This dihedral style can only be used if LAMMPS was built with the
MOLECULE package. See the :doc:`Build package <Build_package>` doc page
for more info.
Related commands
""""""""""""""""
:doc:`dihedral_coeff <dihedral_coeff>`
Default
"""""""
none