Photoionization processes at threshold. I. Threshold photoelectron and photoionization spectra of CO2

15 October 1976

journal article
research article
Published by AIP Publishing in The Journal of Chemical Physics

Vol. 65 (8) , 3316-3325
https://doi.org/10.1063/1.433505

Abstract

A threshold photoelectron spectrometer is described. The instrument has a resolution (FWHM) of 14 meV for states reached by direct photoionization, and 90% rejection of electrons from autoionizing events occuring more than 30 meV above direct ionization thresholds. Detailed threshold photoelectron and total photoionization efficiency spectra are presented for three electronic states (²Π_g, ²Π_u, ²Σ⁺_u) of the CO⁺₂ ion. Vibrational excitation in the symmetric stretching mode is observed for each state with the longest progression occuring for the ²Π_u state. Spin–orbit splitting of the ²Π_g state is readily visible. Autoionization occurs in the vicinity of most of the ²Π_g and ²Π_u levels. There is some indication for production of ions with vibrational excitation in the bending mode.

Keywords

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