O 1s excitation and ionization processes in the CO2 molecule studied via detection of low-energy fluorescence emission

A Kivimäki (1) , J Alvarez-Ruiz (2) , T J Wasowicz (3) , C Callegari (4) , M de Simone (1) , M Alagia (1) , R Richter (4) , M Coreno (5)

1 Laboratorio TASC
2 Instituto de Fusión Nuclear
3 Department of Physics of Electronic Phenomena
4 Sincrotrone Trieste
5 CNR-IMIP

Oxygen 1s excitation and ionization processes in the CO 2 molecule have been studied with dispersed and non-dispersed fluorescence spectroscopy as well as with the vacuum ultraviolet (VUV) photon- photoion coincidence technique. The intensity of the neutral O emission line at 845 nm shows particular sensitivity to coreto-Rydberg excitations and core-valence double excitations, while shape resonances are suppressed. In contrast, the partial fluorescence yield in the wavelength window 300-650 nm and the excitation functions of selected O + and C + emission lines in the wavelength range 400-500 nm display all the absorption features. The relative intensity of ionic emission in the visible range increases towards higher photon energies, which is attributed to O 1s shake-off photoionization. VUV photon - photoion coincidence spectra reveal major contributions from the C + and O + ions and a minor contribution from C 2+. No conclusive changes in the intensity ratios among the different ions are observed above the O 1s threshold. The line shape of the VUV - O + peak carries some information on the initial core excitation.

Mots clés: Physical Sciences

A Kivimäki, J Alvarez-Ruiz, T J Wasowicz, C Callegari, M de Simone, et al.. O 1s excitation and ionization processes in the CO2 molecule studied via detection of low-energy fluorescence emission. Journal of Physics B: Atomic, Molecular and Optical Physics, 2011, 44 (16), pp.165103. ⟨10.1088/0953-4075/44/16/165103⟩. ⟨hal-00645374⟩