"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

:line

fix qmmm command :h3

[Syntax:]

fix ID group-ID qmmm  :pre

ID, group-ID are documented in "fix"_fix.html command
qmmm = style name of this fix command :ul

[Examples:]

fix 1 qmol qmmm

[Description:]

This fix provides functionality to enable a quantum
mechanics/molecular mechanice (QM/MM) coupling of LAMMPS to a quantum
mechanical code.  The current implementation only supports an ONIOM
style mechanical coupling to the "Quantum ESPRESSO"_espresso plane
wave DFT package.  Electrostatic coupling is in preparation and the
interface has been written in a manner that coupling to other QM codes
should be possible without changes to LAMMPS itself.

:link(espresso,http://www.quantum-espresso.org)

The interface code for this is in the lib/qmmm directory of the LAMMPS
distribution and is being made available at this early stage of
development in order to encourage contributions for interfaces to
other QM codes.  This will allow the LAMMPS side of the implementation
to be adapted if necessary before being finalized.

Details about how to use this fix are currently documented in the
description of the QM/MM interface code itself in lib/qmmm/README.

[Restart, fix_modify, output, run start/stop, minimize info:]

No information about this fix is written to "binary restart
files"_restart.html.  None of the "fix_modify"_fix_modify.html options
are relevant to this fix.  No global scalar or vector or per-atom
quantities are stored by this fix for access by various "output
commands"_Section_howto.html#howto_15.  No parameter of this fix can
be used with the {start/stop} keywords of the "run"_run.html command.
This fix is not invoked during "energy minimization"_minimize.html.

[Restrictions:]

This fix is part of the USER-QMMM package.  It is only enabled if
LAMMPS was built with that package. It also requires building a
library provided with LAMMPS.  See the "Making
LAMMPS"_Section_start.html#start_3 section for more info.

The fix is only functional when LAMMPS is built as a library and
linked with a compatible QM program and a QM/MM frontend into a QM/MM
executable.  See the lib/qmmm/README file for details.

[Related commands:] none

[Default:] none
