Fine structure of the neon 18.5-18.7 eV resonances resolved by means of free-free radiative absorptions

Abstract

An experiment on inelastic electron-neon scattering in the field of a tunable dye laser is reported. Resonant free-free transitions are observed between the (Ne+2P12,3/2/)3s2 resonances at 16.1 and 16.2 eV and higher resonances in the region of 18.5-18.7 eV. The population of the upper resonances was monitored by their decay into the Ne I UV-emission channels at 73.6 and 74.3 nm. The fine structure in the upper resonances has been resolved with a resolution of 1.5 meV, which is mainly determined by the width of the lower resonances. For reasons of parity, the classification by Brunt et al. (1977b) of the 18.5-18.7 eV resonances as 2p53p2 seems incorrect. The authors suggest there is evidence for an assignment of part of the structures as 'non-valence' resonances associated with the 2p53p states of neutral neon, and another part as 2p5ns3p resonances.