75 lines
2.3 KiB
ReStructuredText
75 lines
2.3 KiB
ReStructuredText
.. index:: fix qmmm
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fix qmmm 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 qmmm
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* ID, group-ID are documented in :doc:`fix <fix>` command
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* qmmm = 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 qmol qmmm
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Description
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"""""""""""
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This fix provides functionality to enable a quantum
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mechanics/molecular mechanics (QM/MM) coupling of LAMMPS to a quantum
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mechanical code. The current implementation only supports an ONIOM
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style mechanical coupling to the `Quantum ESPRESSO <espresso_>`_ plane
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wave DFT package. Electrostatic coupling is in preparation and the
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interface has been written in a manner that coupling to other QM codes
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should be possible without changes to LAMMPS itself.
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.. _espresso: https://www.quantum-espresso.org
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The interface code for this is in the lib/qmmm directory of the LAMMPS
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distribution and is being made available at this early stage of
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development in order to encourage contributions for interfaces to
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other QM codes. This will allow the LAMMPS side of the implementation
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to be adapted if necessary before being finalized.
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Details about how to use this fix are currently documented in the
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description of the QM/MM interface code itself in lib/qmmm/README.
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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 scalar or vector or per-atom
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quantities are stored by this fix for access by various :doc:`output commands <Howto_output>`. No parameter of this fix can be used
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with the *start/stop* keywords of the :doc:`run <run>` command. This
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fix is not invoked during :doc:`energy minimization <minimize>`.
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Restrictions
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""""""""""""
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This fix is part of the QMMM package. It is only enabled if
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LAMMPS was built with that package. It also requires building a
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library provided with LAMMPS. See the :doc:`Build package <Build_package>` page for more info.
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The fix is only functional when LAMMPS is built as a library and
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linked with a compatible QM program and a QM/MM front end into a QM/MM
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executable. See the lib/qmmm/README file for details.
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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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