Opto-galvanic spectroscopy of a neon discharge: Mechanism studies

Abstract

Irradiation of gaseous discharges with a tunable laser produces easily observed voltage changes at wavelengths which correspond to electronic transitions for species in the discharge. This work reports observations made in the 572–654 nm region on a neon glow discharge, which is operated at 5 torr (670 Pa) pressure and 2–25 mA current. A wide variety of absorption transitions have been detected which originate in the 1s n ( 3P 2,1,0, 1P 1) and 2p n excited states. The resulting voltage signals are both positive and negative, and some transitions exhibit sign changes as a function of discharge current. Some of the results can be interpreted in terms of processes which directly affect the neon metastable atom concentration ( 3P 2, 3P 0) and states also produce voltage changes which can be explained in terms of processes which either enhance or decrease ionization.