Collisional Ionization Equilibrium (CIE) Ion Fractions

For an ionized hydrogen gas, the CIE ion fractions are independent of the metallicity, and are "universal" functions of the gas temperature, as determined by the microscopic steady-state balance between electron impact collisional ionization, electron-ion recombination, and charge transfer reactions.

Download a table of CIE ion fractions versus temperature:  html,  ASCII (text).
(or get time-dependent ion fractions)

Online Tool:
Calculate ion fractions at user-supplied temperature:

Get Ion Fraction at T= K, assuming:
   Collisional ionization equilibrium (CIE).
   Time-dependent cooling, of Z= times solar metallicity gas.

This will take a minute.

Constructed: June 2006, Orly Gnat