*********
GAMESS-UK
*********

.. py:class:: GAMESS-UK

This interface supports energy and gradient evaluations with the
`GAMESS-UK <http://www.cfs.dl.ac.uk/>`_ electronic structure package
(v8, revision 6325 or later)

A GAMESS-UK :ref:`Theory <theories>` object can be specified as follows::

  my_frag = Fragment(...)

  my_theory = GAMESS_UK(frag=my_frag,
                        method='hf',
                        basis='3-21g',
                        ...)

which would then be called as ``theory=my_theory`` in subsequent tasks (see :ref:`Tasks <tasks>`).


General options
===============

.. py:attribute:: memory
   :noindex:

   (default: ``52000000``) Main memory request in words (8 bytes)

.. py:attribute:: harmonic

 Allowed values:

   * ``False``: (default) Do not use spherical harmonic basis functions (as opposed to Cartesians)

   * ``True``: Use spherical harmonic basis functions (as opposed to Cartesians)


SCF options
===========

.. py:attribute:: direct

 Allowed values:

   * ``False``: (default) Switch off :py:attr:`direct`

   * ``True``: Request direct evaluation for a given wavefunction. For open shell systems the SCF type must be specified with ``scftype=``, as the default ``scft direct`` only supports the RHF closed-shell wavefunction.

.. py:attribute:: maxiter

   (default: ``50``) Maximum number of SCF cycles permitted

.. py:attribute:: scf_threshold

   (default: ``5``) SCF convergence threshold :py:attr:`10E-scf_threshold`.

.. py:attribute:: newscf

   (default: ``''``) Free text input for *newscf* directives: can be either Python multi-line string (such as ``'''...'''``) or a filename (e.g., ``'my_newscf.txt'``) of plain text containing multi-line string.


