XC input documentation
======================

Initialize exchange-correlation functional.


Used to initialize class :class:`qimpy.dft.electrons.xc.XC`.

YAML template:
--------------

.. parsed-literal::

   :yamlparam:`qimpy.dft.electrons.xc.XC:functional`: gga-pbe  :yamlcomment:`# Name or list of names of exchange-correlation functionals.`
   :yamlparam:`qimpy.dft.electrons.xc.XC:plus-U`:              :yamlcomment:`# Optional DFT+U correction:`
     :yamlparam:`qimpy.dft.electrons.xc.PlusU:U-values`: [:yamltype:`float`]  :yamlcomment:`# Dictionary of U values by species and orbital names.`
                       

Component classes:
------------------

.. toctree::
    :maxdepth: 1

    PlusU <qimpy.dft.electrons.xc.PlusU>

Parameters:
-----------

functional
++++++++++

*Type:* :yamltype:`string` or :yamltype:`list` of :yamltype:`string`, *Default:*  gga-pbe

Name or list of names of exchange-correlation functionals.
Each entry in the list must be one of the internal functionals:

* gga_pbe
* gga_pbesol
* lda_pw
* lda_pw_prec
* lda_pz
* lda_teter
* lda_vwn
* mgga_revtpss
* mgga_tpss

or a Libxc functional name (if available). Run the code with
functional: 'list' to print the names of available functionals
including those from Libxc (and exit immediately).
The names are case insensitive, and may use hyphens or underscores.

Additionally, for Libxc functionals, a combined xc name will expand
to separate x and c names for convenience, where appropriate.
Therefore, 'gga-pbe' (default) will use the internal PBE GGA,
while 'gga-xc-pbe' will use 'gga_x_pbe' + 'gga_c_pbe' from Libxc.

Finally, each functional name in the list can have an optional
"\*num" suffix (no spaces) to scale the functional by num.
For example, the specification 'gga-pbe\*0.5 lda-pz\*0.5' may be
used to compute a 50-50 mix of two functionals. Warning: there is
no normalization or check to make the fractions of exchange or
correlation to add up to 1.

plus-U
++++++

*Type:* :doc:`PlusU <qimpy.dft.electrons.xc.PlusU>`, *Default:*  :yamlkey:`null`

Optional DFT+U correction.