**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.

(or get time-dependent ion fractions)

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

Constructed: June 2006, Orly Gnat