.. _physics-atomicIonizationRateCollisional:

Atomic Collisional Ionization
=============================

Class providing collisional ionization rate coefficients (in cm\ :math:`^3` s\ :math:`^{-1}`) for atoms of given atomic number and ionization state at a specified electron temperature. Collisional ionization by free electrons competes with photoionization and recombination to set the ionization balance of gas in H**ii** regions, the :term:`IGM`, and the :term:`CGM`.

**Default implementation:** ``atomicIonizationRateCollisionalVerner1996``

Methods
-------

``rate`` → ``double precision``
   Returns the radiative recombination rate in units of cm\ :math:`^3` s\ :math:`^{-1}`.

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

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

.. _physics-atomicIonizationRateCollisionalVerner1996:

``atomicIonizationRateCollisionalVerner1996``
---------------------------------------------

Atomic collisional ionization rates are computed based on the `code <https://web.archive.org/web/20220313133801/https://www.pa.uky.edu/~verner/dima/col/cfit.f>`_ originally written by Dima Verner.

**(Default implementation)**

.. _physics-atomicIonizationRateCollisionalZero:

``atomicIonizationRateCollisionalZero``
---------------------------------------

A null implementation of atomic collisional ionization rates that returns zero for all species and temperatures. Useful for isolating other ionization and recombination processes or for testing purposes.