On the rate of dissociative recombination of H$_3^+$ in recent afterglow plasma experiments

Determination of the rate of the dissociative recombination (DR) in H$_3^+$ has been a cotroversal issue for several decades. At present, the experimental rate about $7-9\times 10^{-8}$ cm$^3$/s at 300~K obtained from several independent storage ring experiments seems to be the most reliable for the ground state of H$_3^+$. There is only one major persistant issue: Two recent experiments in flowing and stationary afterglow plasma with H$_3^+$ made by Glosik and collaborators demonstrated a significant dependence of the DR rate as a function of density of molecular hydrogen, which is present in the plasma. In this study we are suggesting a model that explains the observed dependence of the DR rate on the density of H$_2$. The model is based on the long-living metastable states of H$_3^*$ created in the decaying stationary or flowing plasma.