Astrophysics (index)

Saha Equation

(Saha Ionization Equation, Saha-Langmuir Equation)
(equation relating ionization to temperature)

The Saha Equation (Saha Ionization Equation or Saha-Langmuir Equation) gives the relative count of ions in a particular Ionization State (in this case, number of "missing" electrons) expected based upon the Temperature and other factors regarding a gas. It is used in stellar models. One form:

Ni+1    Zi+1  2
———— = ———— ———— (2π mekT)3/2ei/kT
 Ni     Zi  neh3
  • Ni+1, Ni - Number Density of two successive ionization states i and i+1.
  • Zi+1, Zi - Partition Function for the same (which differs for each ionization state)
  • ne - number-density of free electrons.
  • h - Planck Constant.
  • me - mass of an electron.
  • k - Boltzmann Constant.
  • T - temperature.
  • χi - ionization potential (energy needed to ionize) at ionization state i.

(equation,physics,model)
http://en.wikipedia.org/wiki/Saha-Langmuir equation

Referenced by:
Number Density
State of Ionization
Temperature

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