.. _qmme:

*****
QM/Me
*****


The QM/Me periodic embedding scheme is a QM/MM technique for
surface-adsorbate systems.
See: `J. Meyer and K. Reuter, Angew. Chem. Int. Ed. 2014, 53, 4721-4724. <https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201400066>`_

Currently we only support :py:class:`CP2K` for QM and :py:class:`GULP` for MM. Just similar to standard QM/MM calculations, QM/Me is specified
via the ``QMMM()`` class with the ``scheme='qm/me'`` keyword option::

  my_frag = Fragment(coords=...)

  my_qm = CP2K(...)

  my_mm = GULP(...)

  indices_adsorbate = ...

  my_qmmm = QMMM(frag=...,
                 qm_region=...,
                 qm=my_qm,
                 mm=my_mm,
                 scheme='qm/me',
                 coupling=...,
                 adsorbate=indices_adsorbate,
                 surface='ab',
                 ...)


QM/MM options for QM/Me
=======================

.. py:attribute:: adsorbate

   (default: ``[]``) A list of atom indices of the adsorbate in the fragment

.. py:attribute:: surface

   (default: ``''``) Surface of interest: allowed values are ``'ab'``, ``'ac'``, or ``'bc'``