Excited species in H2, N2, O2 microwave flowing discharges and post-discharges

The density of O and H atoms have been measured by emission spectroscopy and by catalytic probes in a flowing post-discharge reactor. In the post-discharge reactor at 1 torr and a time of 2-3 X 10(-2) s after a 2.45-GHz Ar-10%O-2 discharge (quartz tube of diameter 6 mm) at 60 W, approximately the same values of 1(+/-0-3) X 10(15) cm(-3) oxygen atom densities were obtained by NO titration and by a Ni catalytic probe. In Ar-H-2 post-discharge, the Ni catalytic probe gave a H-atom density of (1-1.2) X 10(15) cm(-3) for an Ar-4%H-2 gas mixture at 3 torr and a time less than 10(-3) s after a microwave discharge of 50 W. (C) 2001 Elsevier Science B.V. All rights reserved.