Electron excitation of neutral and ionic levels in Townsend discharges of argon at high E/N
Institute of Physics, P.O.B. 57, 11001 Belgrade, Yugoslavia
2 Faculty of Physics, University of Belgrade, P.O.Box 550, 11001 Belgrade, Yugoslavia
Revised: 12 April 1999
Published online: 15 August 1999
We have measured the emission coefficients of the 3p levels of ArI: , , , , , and . The data for the , , , and levels were converted to excitation coefficients by using quenching coefficients from the literature. Measurements were performed in the range of E/N between to above except for the level where measurements were done only up to . The data for the emission coefficients for Ar II levels include two 4p' levels with terms and , and three 4p levels with terms , and . The measurements for the ionic levels were done for E/N above up to nearly . The absolute values of the coefficients were obtained from the intensity of the light emitted at the anode in the parallel plate self-sustained Townsend argon discharges. For low E/N the apparent emission coefficients (i.e. the normalized spatial profile of emission) for both neutral and ionic levels increase exponentially in almost the entire discharge gap. At about the exponentially increasing signal was obtained only near the anode, while at the spatial dependence was flat throughout the electrode gap.
PACS: 52.20.Fs – Electron collisions / 52.25.Rv – Emission, absorption, and scattering of visible and infrared radiation / 52.80.Dy – Low-field and Townsend discharges
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999