Vegard-Kaplan bands

Fig. V-9. Energy level diagram of Nj. T) (N—N) = 9.76 eV L-B-H, Lyman-Birge-Hopficld bands V-K, Vegard-Kaplan bands 1, first positive bands 2 +, second positive bands. From Gaydon (8), p. 188, reprinted by permission of Associated Book Publishers Ltd.

In Figure 3 the transient behavior of the Vegard-Kaplan band intensity, I, is shown. The rise of I with time t when the RF excitation is turned on is given by I = I0(l — e t,T) and the decay is given by I = I0e tlT, where t has the same value in both expressions. On the assumption that N2(A3Su+) (called N2 hereafter) decays more slowly than any of its sources, r represents the actual lifetime of N2. All rs so far measured are much larger than the characteristic decay of electron excitation ( 0.1 msec.). 

Figure 3. Transient behavior of the Vegard-Kaplan bands stimulated by a pulsed RF discharge. The vertical scale is relative intensity...

Results. Figure 6 shows the decay rate, when the exciting discharge is turned off, of the 0,3 NO y bands and the 0,5 Vegard-Kaplan band as a function of atomic nitrogen added by the upstream microwave discharge. 

Figures 7 and 8 show the intensity of the 0,5 Vegard-Kaplan band, the 0,3 NO y band, and the 0,6 NO / band in the discharge bulb as a function of the NO concentration that would have existed in the stream if no destruction of NO occurred. Also shown are the responses of the yellow photomultiplier and the ultraviolet photomultiplier, both of which are located at the downstream bulb. Figure 7 represents effects occurring at high discharge power, where [N] and [O] are more easily followed. Phenomena beyond the null (at [NO] 3.5 X 1012) are complex in Figure 7 but simplified in Figure 8, where the excitation power is low. The broken lines in Figure 8 represent behavior expected at low [NO],...

Figure 9 is a plot of the area intensity ratio of 0,3 NO y/0,5 Vegard-Kaplan bands as a function of NO added beyond the null and as a function of the relative response of the yellow phototube to the N02 con-... 

As [NO] increases sharply after the removal of N, the NO y and / bands increase sharply in the discharge and the N2 Vegard-Kaplan bands decrease rapidly when the excitation discharge is operating at low power. Since... 

To obtain k2 from Equation 11, we must experimentally relate the emission intensities more directly to the concentration of the emitting state. If Zy(0,3) represents the absolute intensity of the 0,3 y band of NO and similarly for the Vegard-Kaplan bands, then Equation 11 becomes... 

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