72 lines
1.4 KiB
ReStructuredText
72 lines
1.4 KiB
ReStructuredText
.. index:: angle_style harmonic
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.. index:: angle_style harmonic/intel
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.. index:: angle_style harmonic/kk
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.. index:: angle_style harmonic/omp
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angle_style harmonic command
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============================
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Accelerator Variants: *harmonic/intel*, *harmonic/kk*, *harmonic/omp*
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Syntax
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""""""
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.. code-block:: LAMMPS
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angle_style harmonic
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Examples
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""""""""
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.. code-block:: LAMMPS
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angle_style harmonic
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angle_coeff 1 300.0 107.0
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Description
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"""""""""""
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The *harmonic* angle style uses the potential
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.. math::
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E = K (\theta - \theta_0)^2
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where :math:`\theta_0` is the equilibrium value of the angle, and :math:`K` is a
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prefactor. Note that the usual 1/2 factor is included in :math:`K`.
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The following coefficients must be defined for each angle type via the
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:doc:`angle_coeff <angle_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:`K` (energy)
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* :math:`\theta_0` (degrees)
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:math:`\theta_0` is specified in degrees, but LAMMPS converts it to
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radians internally; hence :math:`K` is effectively energy per
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radian\^2.
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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 angle style can only be used if LAMMPS was built with the
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MOLECULE package. See the :doc:`Build package <Build_package>` doc
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page for more info.
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Related commands
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""""""""""""""""
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:doc:`angle_coeff <angle_coeff>`
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Default
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"""""""
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none
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