Diagnostics and Kinetic Modeling of a Hollow Cathode N₂O Discharge

Abstract

The present work describes a systematic experimental investigation of a N 2 O hollow cathode discharge. The local electron mean energy and density have been determined with a double Langmuir probe. Fourier transform infrared spectroscopy and mass spectrometry have been employed for the measurement of the concentration of the stable species present in the discharge. N 2 O, N 2, O 2, and NO are always identified as the main constituents of the discharge plasma. In addition, NO 2 is found for the first time in a glow discharge of nitrous oxide. As a plausible explanation, a reaction of NO with oxygen atoms adsorbed on the cathode walls is proposed, although homogeneous reactions of vibrationally excited species cannot be discarded. A model based on a reduced set of kinetic equations including electron dissociation, gas-phase reactions, and gas−surface processes can give a global account of the measured data for all the experimental conditions used. The results are discussed and, when possible, compared to previous works on other types of N 2 O glow discharges.