REASSESSMENT OF THE DISSOCIATIVE RECOMBINATION OF N₂H⁺AT CRYRING

Abstract

The dissociative recombination (DR) of N2H+ has been reinvestigated at the heavy ion storage ring CRYRING at the Manne Siegbahn Laboratory in Stockholm, Sweden. Thermal rate coefficients for electron temperatures between 10 and 1000 K have been deduced. We show that electron recombination is expected to play an approximately equally important role as CO in the removal of N2H+ in dark interstellar clouds. We note that a deeper knowledge on the influence of the ions' rotational temperature in the DR of N2H+ would be helpful to set further constraints on the relative importance of the different destruction mechanisms for N2H+ in these environments. The branching fractions in the DR of N2H+ have been reinvestigated at ∼0 eV relative kinetic energy, showing a strong dominance of the N2 + H production channel (93+4− 2%) with the rest leading to NH + N. These results are in good agreement with flowing afterglow experiments and in disagreement with an earlier measurement at CRYRING.