.. _physics-atomicIonizationPotential:

Atomic Ionization Potentials
============================

Class providing atomic ionization potentials (in eV) for atoms of given atomic number in a specified ionization state (i.e. with a given number of remaining electrons). Ionization potentials set the energy threshold for photo-ionization and are used in computing photo-ionization rates from a given radiation field spectrum in :term:`IGM` and :term:`CGM` calculations.

**Default implementation:** ``atomicIonizationPotentialVerner``

Methods
-------

``potential`` → ``double precision``
   Returns the ionization potential (in units of eV) for a given atom in a given ionization state.

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

.. _physics-atomicIonizationPotentialVerner:

``atomicIonizationPotentialVerner``
-----------------------------------

Implements an atomic ionization potential class, which provides potentials for all ionization stages of all atoms from H to Zn using data taken from Dima Verner's `code <https://web.archive.org/web/20220313133801/https://www.pa.uky.edu/~verner/dima/col/cfit.f>`_.

**(Default implementation)**