PX282 - C9f - deionized hydrogen

a deionized hydrogen is a hydrogen atom with an extra electron, H $^{-}$
it is barely stable, with an ionization energy, $χ_{i} = 0.75 e V$ (c.f. $χ_{H} = 13.6 e V$ )
this is makes it very easy to ionize, and a key source of continuum opacity
using the saha equation to find the ratio:

\frac{N_{H^{+}}}{N_{H}} = \frac{C}{N_{e}} T^{\frac{3}{2}} \frac{2 U_{H^{+}} (T)}{U_{H} (T)} \exp (- \frac{χ_{i} (H)}{k_{B} T})

\frac{N_{H}}{N_{H^{-}}} = \frac{C}{N_{e}} T^{\frac{3}{2}} \frac{2 U_{H} (T)}{U_{H^{-}} (T)} \exp (- \frac{χ_{i} (H^{-})}{k_{B} T})

solar atmosphere:
- $T \sim 6000 K$
- $N_{e} \sim 1.2 \times 10^{14} m^{- 3}$
- $U_{H} (T) = 2$ , $U_{H^{+}} (T) = 1$ , $U_{H^{-}} (T) = 1$

\frac{N_{H^{+}}}{N_{H}} = 3 \times 10^{- 4}; \frac{N_{H^{-}}}{N_{H}} = 1 \times 10^{- 8}