Metastable xenon reactions

The quenching of Xe(6s, 3p ) metastable atoms by phosgene has been studied [1146,1844], and the vibrational energy transfer monitored [2004]. The reaction of excited xenon atoms (3 or 3p ) th phosgene generates XeCl(B,C), the emission from which, XeCl(B-.X ) and XeCl(C-A), has enabled vibrational relaxation and transfer between the B and C states to be studied in some detail [263,558]. 

The addition of 0.07% xenon brings about a 30% reduction in the negative residual current and the exponential slope increases so that experimentally a = 1.03 X 10"16 cm.2. This cannot be accounted for by assuming that the only additional loss is that arising from the ionization of xenon. At a concentration of only 7 X 10 2 atom %, this would imply a cross section for ionization of xenon equal to 228 X 10 16 cm.2—about a factor of 40 higher than the known o- of xenon (11) for 100 e.v. electrons. A more reasonable inference is that the loss of neon metastables by the Penning reaction ... 

It is curious that the most used Q source for an XeCl laser (either e-beam or discharge excited) is HQ and to first order neither of the above reaction schemes is relevant. The reaction e + HQ -> H + Q is 1(X) times too slow to allow for sufficient laser gain to be generated. Moreover, the harpoon mechanism fiom xenon metastables does not produce XeQ emission in high yield. The above considerations are not true for a based XeCl laser, but materials handling and background absorption make this a less desirable source of Q. 

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