Ionization potential depression and its effect on Saha ionization equation in stellar environment

The ionization potential is the energy required to free an atomic bound electron to continuum state. The ionization potential of an atom embedded in matter in thermodynamic equilibrium gets reduced. Then the energy of zero-kinetic-energy electron becomes non-zero in the medium. One can think of it as the lowering of the continuum of an atom or ion when surrounding is non-empty. This phenomenon is known as Ionization Potential Depression (IPD). The ionization potential is an important ingredient while using Saha Ionization Equation (SIE). SIE deals with ionization potential of every charge state while providing a clear view about the fractional percentage of different ionized states of a particular species as a function of temperature and free electron number density. For this reason, modification of ionization potential is essential when solving Saha Ionization Equation. Moreover, for a precise view of various nuclear properties, such as β-decay processes in stellar environment, the accurate idea of fractional percentages of various ions of an atomic species is necessary. For this purpose, an exact solution of SIE is very essential. To summarize, we have compared three different models for IPD in stellar environments. The modified ionization potential is used in solving the Saha ionization equation. At relatively lower temperatures the inclusion of IPD has a noticeable impact on the results