********
FHI-aims
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.. py:class:: FHIaims

This interface supports energy and gradient evaluations with the
`FHI-aims <https://aimsclub.fhi-berlin.mpg.de/>`_ electronic structure package.

An FHI-aims :ref:`Theory <theories>` object can be specified as follows::

  my_frag = Fragment(...)

  my_theory = FHIaims(frag=my_frag,
                     settings='fhiaims.settings',
                     basis='fhiaims.basis',
                     ...)

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

Note the FHI-aims interface is currently a prototype with most
settings contained in the ``settings`` file which you must provide
separate to the main input. This will change in future versions of
ChemShell.

Compilation
===========

The FHI-aims interface can be soft-coded (working via a system call) or 
hard-coded as a library, as outlined in the ``INSTALL`` instructions.

When building the executable to use via the soft-coded interface, ChemShell will
search for ``aims.x`` in the directories of the ``$PATH`` environment variable. 
One can create a link to the datestamped executable with this generic name by 
setting ``set(TARGET_NAME aims.x CACHE STRING "")`` in the CMake compilation; 
for a Makefile build, this link is generated automatically.


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

.. py:attribute:: settings

   File containing settings in FHI-aims input format.

.. py:attribute:: basis
   :noindex:

   File containing basis set definition in FHI-aims format.

