Dissociative Excitation of Vacuum Ultraviolet Emission Features by Electron Impact on Molecular Gases. III. CO2

Abstract

Vacuum ultraviolet multiplets of CI, CII, and OI have been produced by electron impact on CO2. Absolute emission cross sections for these multiplets have been measured from threshold to 350 eV. The electrostatically focussed electron gun used in this series of experiments is described in detail. The atomic multiplets which were produced by dissociative excitation of CO2 and the cross sections at 100 eV are: OI(2p4 3P−2p33s 3S) 1304 Å−1.04× 10−18cm2± 18%; CI(2s22p2 3P−2s2p3 3P0) 1329 Å−2.67× 10−19 cm2± 21%; CI(2s22p2 3P−2s2p3 3D0) 1561 Å−7.50 × 10−19 cm2± 30%; CI(2p2 3P−2p3s 3P0) 1657 Å−1.45× 10−18 cm2 ± 23%; CII(2s22p 2P0−-2s2p2 2D) 1335 Å−7.60× 10−19 cm2± 22%; and CII (2s2p2 2D−2p3 2D0) 1324 Å−1.33 × 10−20 cm2± 23%. The dependence of the excitation functions on electron energy shows that these multiplets are produced by electric-dipole-allowed transitions in CO2.