.. _physics-gauntFactor:

Gaunt Factors
=============

Class providing thermally averaged Gaunt factors :math:`\bar{g}(T, Z, N_\mathrm{e})` for free-free (bremsstrahlung) radiation from a plasma of given atomic number and ionization state at temperature :math:`T`. Gaunt factors are quantum mechanical correction factors to the classical free-free emission rate and enter into the computation of bremsstrahlung cooling and thermal emission spectra from hot gas.

**Default implementation:** ``gauntFactorSutherland1998``

Methods
-------

``total`` → ``double precision``
   Returns the thermally averaged, total Gaunt factor for free-free (bremsstrahlung) emission from a plasma, given the atomic number, electron number, and temperature. This dimensionless quantum-mechanical correction factor modifies the classical free-free emission rate.

   * ``integer , intent(in ) :: atomicNumber, electronNumber``

   * ``double precision, intent(in ) :: temperature``

.. _physics-gauntFactorSutherland1998:

``gauntFactorSutherland1998``
-----------------------------

Gaunt factors are computed using the fitting function of :cite:t:`sutherland_accurate_1998`.

**(Default implementation)**

.. _physics-gauntFactorVanHoof2014:

``gauntFactorVanHoof2014``
--------------------------

Gaunt factors are computed using the fitting function of :cite:t:`van_hoof_accurate_2014`.