# Finding the ratios of diatomic, monatomic and ionized hydrogen

1. Feb 7, 2013

### omoplata

Hi,

Would a clump of gas in space have some diatomic molecules in it as well? If it does, how do we find the ratio?

I know that hydrogen gas at room temperature on earth is diatomic. So I guess the state of the gas molecules change like this.

Diatomic molecules -> Monatomic ground state -> Monatomic first excited -> ... so on until ionization.

Or do diatomic states have their own excited states as electrons go on to higher and higher energy levels?

I know that in a gas in thermal equilibrium, the ratio of two populations is given by Boltzmann distribution: $\frac{n_j}{n_i} = \frac{g_j}{g_i} e^{-[(E_j-E_i)/kT]}$
I also know that I can use this equation to find the ratios of monatomic hydrogen in different excited states. For example, the ratio of hydrogen in ground state to the first excited state.
Can I use it to find the ratio of diatomic ground state molecules to monatomic ground state molecules as well? I guess all I have to do is just put in the corresponding energy values?