OPTICAL DIAGNOSTICS OF ACTIVE SPECIES IN N-2 MICROWAVE FLOWING POSTDISCHARGES

The nitrogen atom density is determined from NO titration and from the N-2 first-positive-band intensity. The main kinetic reactions which p roduce the N-2 first-positive-band emission in the afterglow are the f ollowing: [GRAPHICS] in an early afterglow at times 10(-3)-10(-2)s and N + N + N-2 --> N-2(B, upsilon') + N-2 in the full afterglow period ( 10(-3)-10(-1)s). From the N-2(B, upsilon'-A, upsilon '') first-positiv e-band intensity, parts of the above reactions have been established a long a 2.45 GHz, 120 W N-2 flowing post-discharge at 5-130 hPa gas pre ssure and at 0.2-1 standard 1 min(-1) flow rate. It has been found tha t the NO titration method is only available in the late afterglow wher e the second reaction is dominant. By discriminating the second reacti on from the first reaction, the first-positive-band intensity allows t he N atom density determination in the post-discharge, along a larger domain than with NO titration including the end of the early afterglow . Furthermore, the first reactions contribute to produce highly excite d levels up to N-2(B, upsilon' = 17, 18) whose vibrational distributio n is given in the present paper. These levels, whose N-2(B, upsilon' > 13-15) states are autodissociative states are not created by the seco nd reaction. Consequently, this is also a second method for specifying the afterglow parts where the above reactions are the dominant kineti c processes.