DISSOCIATIVE RECOMBINATION MEASUREMENTS OF HCl⁺ USING AN ION STORAGE RING

Abstract

We have measured dissociative recombination of HCl+ with electrons using a\nmerged beams configuration at the heavy-ion storage ring TSR located at the Max\nPlanck Institute for Nuclear Physics in Heidelberg, Germany. We present the\nmeasured absolute merged beams recombination rate coefficient for collision\nenergies from 0 to 4.5 eV. We have also developed a new method for deriving the\ncross section from the measurements. Our approach does not suffer from\napproximations made by previously used methods. The cross section was\ntransformed to a plasma rate coefficient for the electron temperature range\nfrom T=10 to 5000 K. We show that the previously used HCl+ DR data\nunderestimate the plasma rate coefficient by a factor of 1.5 at T=10 K and\noverestimate it by a factor of 3.0 at T=300 K. We also find that the new data\nmay partly explain existing discrepancies between observed abundances of\nchlorine-bearing molecules and their astrochemical models.\n