A remeasurement of the products for electron recombination of N2H+ using a new technique: no significant NH+N production

A remeasurement of the product distribution from dissociative electron-ion recombination (DR) of N2H+ has been made using a new technique. The technique employs electron impact to ionize the neutral products prior to detection by a quadrupole mass analyzer. Two experimental approaches, both using pulsed gas techniques, isolate and quantify the DR products. In one approach, an electron-attaching gas is pulsed into a flowing afterglow to transiently quench DR. Results from this approach give an upper limit of 5% for the NH+N product channel. In the second approach, the reagent gas N2 is pulsed. The absolute percentages of products were monitored versus initial N2 concentration. Results from this approach also give an upper limit of 5% for NH+N production. This establishes that N2+H is the dominant channel, being at least between 95 and 100%, and that there is no significant NH production contrary to a recent storage ring measurement that yielded 64% NH+N and 36% N2+H. Possible reasons for this dramatic difference are discussed.