A remeasurement of the products for electron recombination of N2H+ using a new technique: No significant NH plus N production
. J Phys Chem A 2007
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 N-2 is pulsed. The absolute percentages of products were monitored versus initial N-2 concentration. Results from this approach also give an upper limit of 5% for NH + N production. This establishes that N-2 + 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% N-2 + H. Possible reasons for this dramatic difference are discussed.