J. Phys. III France
Volume 6, Number 9, September 1996
Page(s) 1189 - 1204
DOI: 10.1051/jp3:1996178
J. Phys. III France 6 (1996) 1189-1204

Time Resolved Diagnostics for Kinetic Studies in N 2/O 2 Pulsed rf Discharges

S. De Benedictis and G. Dilecce

Centro di Studio per la Chimica dei Plasmi C.N.R., c/o Dipartimento di Chimica Università di Bari, Via Orabona 4, 70126 Bari, Italy

(Received 7 February 1996, revised 5 April 1996, accepted 29 April 1996)

Time resolved optical diagnostics have been applied to the study of energy transfers in N 2/O 2 pulsed radio-frequency discharge. N 2(A $^{3}\Sigma^{+}_{\rm u}$ and NO(X $^{2}\Pi$) have been measured by Laser Induced Fluorescence, and NO- $\gamma$ band by Emission Spectroscopy. The analysis in discharge and post discharge as a function of O 2 percentage allows to guess the main mechanisms correlating the relaxation of these species in the post-discharge. NO- $\gamma$ bands in N 2/O 2 discharge are mainly excited by N 2(A) + NO(X) collisions. The decay rates of N 2(A) can be accounted for by O, NO and O 2 quenching. NO ground state density, measured by LIF, varies with O 2 percentages showing a bell shape profile with a broad maximum. Some EEDF measured by Langmuir probe under continuous discharge conditions show that O 2 addition, even in few percents, strongly reduces the density of low energy electrons.

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