.. _physics-atomicRecombinationRateRadiative:

Atomic Radiative Recombination
==============================

Class providing radiative recombination rate coefficients (in cm\ :math:`^3` s\ :math:`^{-1}`) for ions of given atomic number and ionization state at a specified electron temperature. Case A (all recombinations) and case B (excluding recombinations directly to the ground state, for optically thick nebulae) coefficients are supported. These rates are used in ionization equilibrium calculations and in determining the recombination line luminosities of nebulae.

**Default implementation:** ``atomicRecombinationRateRadiativeVerner1996``

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``

   * ``type (enumerationRecombinationCaseType), intent(in ), optional :: level``

.. _physics-atomicRecombinationRateRadiativeComputed:

``atomicRecombinationRateRadiativeComputed``
--------------------------------------------

Atomic radiative recombination rates computed from the corresponding photoionization cross section using detailed balance (i.e. the Milne relation---see for example "Astrophysics of the Diffuse Universe" by Dopita & Sutherland, 2004, Springer Science & Business Media, section 5.3.3).

.. _physics-atomicRecombinationRateRadiativeFixed:

``atomicRecombinationRateRadiativeFixed``
-----------------------------------------

Computes atomic radiative recombination rates using a fixed, constant rate coefficient specified by ``[rateCoefficient]`` in units of cm\ :math:`^3` s\ :math:`^{-1}`. This provides a simple, temperature-independent approximation to the recombination rate for use in ionization and cooling calculations.

**Parameters**

* ``[rateCoefficient]`` (real) — The rate coefficient (in units of cm\ :math:`^3` s\ :math:`^{-1}`) for radiative recombination.

.. _physics-atomicRecombinationRateRadiativeVerner1996:

``atomicRecombinationRateRadiativeVerner1996``
----------------------------------------------

Atomic radiative recombination rates are computed based on the `code <https://web.archive.org/web/20220313133758/https://www.pa.uky.edu/~verner/dima/rec/rrfit.f>`_ originally written by Dima Verner.

**(Default implementation)**