Excitation of the 1s5 and 1s4 levels of neon by low-energy electrons.

Abstract

Excitation coefficients for production of 1${s}_{5}$ and 1${s}_{4}$ levels (Paschen notation) of neon in collisions with low-energy electrons have been measured using a drift-tube technique combined with laser absorption and laser-induced fluorescence techniques. The absorption and fluorescence signals have been analyzed using coupled rate equations which include the effects of population mixing among these levels in collisions with neon atoms. The excitation coefficients for the metastable and resonance levels ${\ensuremath{\alpha}}_{M}$/N and ${\ensuremath{\alpha}}_{R}$/N have been obtained as functions of the electric field to gas density ratio E/N. The measured values of ${\ensuremath{\alpha}}_{M}$/N vary from 1.3\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}24}$ ${\mathrm{m}}^{2}$ at E/N=1.6\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}21}$ V ${\mathrm{m}}^{2}$ to 6.5\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}22}$ ${\mathrm{m}}^{2}$ at 3.0\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}19}$ V ${\mathrm{m}}^{2}$. The values of ${\ensuremath{\alpha}}_{R}$/N are comparable in the experimental E/N range. The experimental excitation coefficients are in agreement with values calculated from a Boltzmann analysis using a recommended set of electron excitation cross sections derived from published experimental electron beam data.