forked from lijiext/lammps
74 lines
2.3 KiB
Plaintext
74 lines
2.3 KiB
Plaintext
.. 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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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 mechanice (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: http://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 :ref:`output commands <howto_15>`. No parameter of this fix can
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be used with the *start/stop* keywords of the :doc:`run <run>` command.
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This 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 USER-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 :ref:`Making LAMMPS <start_3>` section 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 frontend into a QM/MM
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executable. See the lib/qmmm/README file for details.
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**Related commands:** none
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**Default:** none
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.. _lws: http://lammps.sandia.gov
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.. _ld: Manual.html
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.. _lc: Section_commands.html#comm
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