Trihydrogen Cation - Destruction

Destruction

The information for this section was also from a paper by Eric Herbst. There are many destruction reactions for H₃+. The dominant destruction pathway in dense interstellar clouds is by proton transfer with a neutral collision partner. The most likely candidate for a destructive collision partner is the second most abundant molecule in space, CO.

H₃+ + CO → HCO+ + H₂

The significant product of this reaction is HCO+, an important molecule for interstellar chemistry. Its strong dipole and high abundance make it easily detectable by radioastronomy. H₃+ can also react with atomic oxygen to form OH+ and H₂.

H₃+ + O → OH+ + H₂

OH+ then usually reacts with more H₂ to create further hydrogenated molecules.

OH+ + H₂ → OH₂+ + H

OH₂+ + H₂ → OH₃+ + H

At this point, the reaction between OH₃+ and H₂ is no longer exothermic in interstellar clouds. The most common destruction pathway for OH₃+ is dissociative recombination, yielding four possible sets of products: H₂O + H, OH + H₂, OH + 2H, and O + H₂ + H. While water is a possible product of this reaction, it is not a very efficient product. Different experiments have suggested that water is created anywhere from 5–33% of the time. Water formation on grains is still considered the primary source of water in the interstellar medium.

The most common destruction pathway of H₃+ in diffuse interstellar clouds is dissociative recombination. This reaction has multiple products. The major product is dissociation into three hydrogen atoms, which occurs roughly 75% of the time. The minor product is H₂ and H, which occurs roughly 25% of the time.