The behavior of nitric oxide in glow discharges

Mass spectrographic analyses were conducted to determine the positive ions and neutral species in glow discharges containing NO for pressures from 10 to 75 Torr. The three gas mixtures investigated included 1.0% NO in He, 0.55% NO in N2, and 2.5% each of CO and CO2 plus 0.55% NO in N2. Various means were utilized for the application of electrical power: directly coupled dc and 60 Hz ac, capacitively coupled 60 Hz ac, and inductively coupled 3.0 MHz rf. Nitric oxide was readily dissociated in the discharges, resulting in the formation of N2 and O2—or N2 and CO2 when CO was present initially. Introduction of the minimum excitation necessary to maintain a uniform glow discharge was most effective; increasing the applied power beyond this minimum point served primarily to induce secondary reactions among the products of the NO decomposition.