Saha function is a function of temperature and pressure, high temperature favoring ionization and high pressure favoring recombination. The equation tells us the relative numbers of the three types of...Saha function is a function of temperature and pressure, high temperature favoring ionization and high pressure favoring recombination. The equation tells us the relative numbers of the three types of particle (i.e. the degree of ionization) in an equilibrium situation when the number of ionizations per second is equal to the number of recombinations per second.