Ionization Energy
The minimum energy required to detach an electron from a neutral atom or ion, initiating gas-to-plasma phase transformation.
Governing formula
E_ion = h ν - K_e (Saha Ionization Equation)
SI unit
eV (Electron-Volts)
In depth
Creating a plasma requires overcoming atomic binding energy. At thermal equilibrium, the fractional ionization degree as a function of temperature T and electron density n_e is calculated using the Saha ionization equation.
Examples in the real world
Calculating thermal ionization thresholds in electric arc welders, neon discharge tubes, and stellar interiors.