Dissociative Recombination of Ne-2(+) Molecular Ions with Electrons: Population of Ne(2p(5)4p) Atoms in a Decaying Plasma

摘要

Decaying neon plasma has been investigated by kinetic spectroscopy. The experimental conditions were neon pressure of 0.2-152 Torr and electron density in the initial stage of decay [e] <= 5 x 10(10) cm(-3). The plasma was created by a pulsed barrier discharge with electrodes on the outer surface of a cylindrical glass tube. The discharge frequency was 40-160 Hz. It has been shown based on a comparative analysis of the dependences of the intensities of spectral lines on the time and electron temperature in the afterglow that the 2p(5)4p levels are clearly divided into two groups in terms of population mechanisms. The lower levels (from 3p(10) to 3p(3) (Paschen notations)) are related to dissociative recombination of Ne-2(+) molecular ions with electrons, and the lines emitted by them behaved identically to the lines of the transitions 2p(5)3s <- 2p(5)3p and 2p(5)3p <- 2p(5)3d up to pressures of 0.6 Torr. The kinetics of the upper levels (3p(5), 3p(2), 3p(4), and 3p(1)) had a more complicated character, and, at low pressures, the populations of all 2p(5)4p levels were related to a collisional-radiative recombination of Ne+ ions. Significant differences in the dependences of the relative populations of 3d- and 4p levels on neon pressure are discussed.