DECAY OF METASTABLE Ne(3P2-ATOMS

Overview & Synopsis

Investigations on the destruction rates of metastable atoms as a function of gas density in neon and the other noble gases have been carried out in recent years. The experimental method most frequently used is the optical absorption technique. (1, 2, 3, 4). A tunable dye laser was used in (5) to study non resonant fluorescence in the afterglow of a positive column in neon to determine the decay frequency of 3s-states. In another experiment a time resolved study of the vacuum U.V. emission of Ne (1P1) and 3 Ne ( 3P1) States was carried out to study the Ne (3P2) decay (6). At this moment the numerous mechanisms which govern the 3P2 decay are fairly well understood (1, 5). In the present work the afterglow of a Townsend discharge (T.D.) is used for mass spectrometrical determination of the Ne (3P2) decay at 77 and 295 K, using the Penning ionisation of N2 impurities as a diagnostic reaction. Current densities smaller than 10-8 A/cm2 provide cumulative processes, e.g. dissociative recombination, not to take place.