70 lines
1.5 KiB
ReStructuredText
70 lines
1.5 KiB
ReStructuredText
.. index:: angle_style gaussian
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angle_style gaussian command
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================================
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Syntax
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""""""
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.. code-block:: LAMMPS
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angle_style gaussian
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Examples
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""""""""
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.. code-block:: LAMMPS
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angle_style gaussian
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angle_coeff 1 300.0 2 0.0128 0.375 80.0 0.0730 0.148 123.0
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Description
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"""""""""""
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The *gaussian* angle style uses the potential:
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.. math::
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E = -k_B T ln\left(\sum_{i=1}^{n} \frac{A_i}{w_i \sqrt{\pi/2}} exp\left( \frac{-(\theta-\theta_{i})^2}{w_i^2})\right) \right)
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This analytical form is a suitable potential for obtaining
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mesoscale effective force fields which can reproduce target atomistic distributions :ref:`(Milano) <Milano1>`
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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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* T temperature at which the potential was derived
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* :math:`n` (integer >=1)
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* :math:`A_1` (-)
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* :math:`w_1` (-)
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* :math:`\theta_1` (degrees)
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* ...
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* :math:`A_n` (-)
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* :math:`w_n` (-)
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* :math:`\theta_n` (degrees)
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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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----------
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.. _Milano1:
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**(Milano)** G. Milano, S. Goudeau, F. Mueller-Plathe, J. Polym. Sci. B Polym. Phys. 43, 871 (2005).
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