Hi this may sound like a simple question but I'm trying to find out the relative abundance of hydrogen in its various forms in space: H, H+, H-, H2, H2+, H2- I'd like to know these for our stellar neighborhood involving the solar wind and also for interstellar space outside the heliopause. I was hoping to use the energy required to remove an electron from hydrogen vs. the energy to add an additional one. I looked at ionization energy but it's been too long since I studied it in school. I was wondering if the Bohr model might work for this simple case: https://en.wikipedia.org/wiki/Ionization_energy#Electrostatic_explanation https://en.wikipedia.org/wiki/Bohr_model#Rydberg_formula * Could someone direct me to a table showing the energy required to add or remove an electron from H to create H- (hydride) and H+ (hydron), or are they identical? * The same for H2 to H2- and H2+ * Does someone know the ratio of H to H2 in the universe? Perhaps from there we can make a good guess as to the relative abundances. I also would like to find these ratios for helium but it's not as critical (I'm studying aspects of the Bussard ramjet and Zubrin solar brake and how much would be lost to some ions going the opposite direction).