Mass-Spectrometric Studies of Corona Discharges in Air at Atmospheric Pressures

Abstract

Mass‐spectrometric studies of the ionic species formed in corona discharges in nitrogen, oxygen, and air have been carried out at water concentrations from 1.7×10−2 to 0.65 mole % and total pressures up to one atmosphere. The importance of water in this system has been demonstrated by the dominant presence of (H2O) n H+ ion clusters at water concentrations as low as 4.1×10−2 mole %. Evidence is presented for the formation (HO2)+ and (N2H)+ ions as possible intermediates in the formation of these clusters. It is argued that hydride formation by the primary ions and possibly charge‐exchangereaction with water molecules followed by proton‐transfer reactions are the mechanisms by which these clusters are produced. Simple hydration of other ionic species of the discharge, e.g., O2 +(H2O) n , NO+(H2O) n , and (NO2 +) (H2O) n , at water concentrations below 5.5×10−2 mole % have also been observed.