83 lines
2.1 KiB
ReStructuredText
83 lines
2.1 KiB
ReStructuredText
.. index:: fix nvk
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fix nvk command
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===============
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Syntax
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""""""
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.. parsed-literal::
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fix ID group-ID nvk
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* ID, group-ID are documented in :doc:`fix <fix>` command
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* nvk = style name of this fix command
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Examples
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""""""""
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.. code-block:: LAMMPS
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fix 1 all nvk
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Description
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"""""""""""
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Perform constant kinetic energy integration using the Gaussian
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thermostat to update position and velocity for atoms in the group each
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timestep. V is volume; K is kinetic energy. This creates a system
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trajectory consistent with the isokinetic ensemble.
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The equations of motion used are those of Minary et al in
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:ref:`(Minary) <nvk-Minary>`, a variant of those initially given by Zhang in
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:ref:`(Zhang) <nvk-Zhang>`.
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The kinetic energy will be held constant at its value given when fix
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nvk is initiated. If a different kinetic energy is desired, the
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:doc:`velocity <velocity>` command should be used to change the kinetic
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energy prior to this fix.
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----------
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Restart, fix_modify, output, run start/stop, minimize info
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"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
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No information about this fix is written to :doc:`binary restart files <restart>`. None of the :doc:`fix_modify <fix_modify>` options
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are relevant to this fix. No global or per-atom quantities are stored
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by this fix for access by various :doc:`output commands <Howto_output>`.
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No parameter of this fix can be used with the *start/stop* keywords of
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the :doc:`run <run>` command. This fix is not invoked during :doc:`energy minimization <minimize>`.
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Restrictions
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""""""""""""
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The Gaussian thermostat only works when it is applied to all atoms in
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the simulation box. Therefore, the group must be set to all.
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This fix has not yet been implemented to work with the RESPA integrator.
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This fix is part of the EXTRA-FIX package. It is only enabled if
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LAMMPS was built with that package. See the
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:doc:`Build package <Build_package>` page for more info.
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Related commands
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""""""""""""""""
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none
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Default
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"""""""
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none
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----------
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.. _nvk-Minary:
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**(Minary)** Minary, Martyna, and Tuckerman, J Chem Phys, 18, 2510 (2003).
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.. _nvk-Zhang:
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**(Zhang)** Zhang, J Chem Phys, 106, 6102 (1997).
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