Enhanced abundance of primordial HeH+

Abstract

Astrochemistry Though only recently detected in space, the helium hydride ion (HeH+) is thought to be the first molecule ever to have formed in the early Universe. Novotný et al. report state-specific rate coefficients for the dissociative reaction of HeH+ with electrons, obtained using a cryogenic ion storage ring combined with a merged electron beam (see the Perspective by Bovino and Galli). They detect substantial rotational dependence and a decrease of the rates for the lowest states of HeH+, far below the values listed in astrochemistry databases and those previously applied in early-Universe models. These results suggest high abundance of this important primordial molecule at redshifts of first star and galaxy formation. Science , this issue p. [676][1]; see also p. [639][2] [1]: /lookup/doi/10.1126/science.aax5921 [2]: /lookup/doi/10.1126/science.aay5825