xtb
======

This option controls the xTB calculation options. 

.. contents::
   :local:

.. option:: chrg

   .. list-table::
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      :widths: 5 20
   
      * - Value
        - An integer
      * - Default
        - ``0``

   The total charge of the system.

.. option:: uhf

   .. list-table::
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      :widths: 5 20
   
      * - Value
        - An integer
      * - Default
        - ``0``
   
   The number of unpaired electrons.

.. option:: gfn

   .. list-table::
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      :widths: 5 20
   
      * - Value
        - ``1`` The GFN1-xTB Hamiltonian. This is more reliable for inorganic compounds, like metallic clusters or quantum dots.
      * - 
        - ``2`` The GFN2-xTB Hamiltonian. This is useful for organic molecules.
      * - Default
        - ``2``
   
   Define the xTB Hamiltonian type.

.. option:: gbsa

   .. list-table::
      :stub-columns: 1
      :widths: 5 20
   
      * - Value
        - ``H2O`` 
      * -         
        - ``Acetone``        
      * - 
        - ``Acetonitrile``
      * - 
        - ``Aniline``
      * - 
        - ``Benzaldehyde``
      * -         
        - ``Benzene``
      * -         
        - ``CH2Cl2``
      * -         
        - ``CHCl3``
      * -         
        - ``CS2``
      * -         
        - ``Dioxane``
      * -         
        - ``DMF``
      * -         
        - ``DMSO``
      * -         
        - ``Ether``
      * -         
        - ``Ethylacetate``
      * -         
        - ``Furane``
      * -         
        - ``Hexadecane``
      * -         
        - ``Hexane``
      * -         
        - ``Nitromethane``
      * -         
        - ``Octanol``
      * -         
        - ``Phenol``
      * -         
        - ``Toluene``
      * -         
        - ``THF``                
      * - Default
        - None

   The solvent name. If it is not given, the xTB is calculated in the gas phase. Otherwise, generalized Born model will be used to consider solvent effects.