SURFACE RECOMBINATION OF ATOMS IN A NITROGEN AFTERGLOW

The surface recombination of nitrogen atoms in afterglow is studied by the time delay method, accompanied by the macrokinetic diffusive model. The method consists of the measurement of the dependence of the mean value of the breakdown time delay on afterglow period ($) over bar t(d)=f(tau) and fitting of the data by the model that was developed. Excited N-2(A (3) Sigma(u)(+)) nitrogen molecules formed in the surface-catalyzed recombination on cathode produce secondary electrons. The electrons entering the interelectrode space determine the time delay in electrical breakdown. The time delay method is very efficient in nitrogen atom detection down to a natural radioactivity level. By fitting the calculated curve to the experimental data, we have: (1) shown that the nitrogen atom recombination on the glass container walls is second-order in N while the recombination on the copper electrode is the first order; (2) determined the value of-the surface recombination coefficient for molybdenum glass; (3) determined the combined probability of N-2(A (3) Sigma(u)(+)) metastable formation by recombination at electrode surface and of secondary electron emission. Furthermore, we derive the adsorption isotherm of nitrogen atoms on molybdenum glass, the type of recombination mechanism and the dependence of the activation energy; for desorption (or the heat of adsorption) on the fractional coverage.