Photodissociation of condensed carbon dioxide below the gas phase thresholds

Electron stimulated desorption from solid CO2 and a hydrogen containing CO2 matrix: A comparative study

“…25 Correspondingly the two observed thresholds in the solid phase are assigned to second and third limit observed in the gas phase. The absence of O ϩ ion yield below 21.5 eV, as has been discussed previously, 9,10 is because the O ϩ ion can desorbed only if the charge is localized on the terminal oxygen atom of a CO 2 molecule for a long enough period. CO 2 is linear molecule with a ground-state electronic configuration, 1 ⌺ g ϩ , which may be written as: ͑core͒ 6 (3 g ) 2 (2 u ) 2 (4 g ) 2 (3 u ) 2 (1 u ) 4 (1 g ) 4 (2 u ) 0 .…”

“…This work is an extension of very recent photon 9 and electron 10 stimulated desorption studies ͑commonly used acronyms PSD and ESD, respectively͒ in the vacuum ultraviolet ͑VUV͒ energy range on solid CO 2 matrices. In both studies, at very low photon ͑electron͒ fluxes O 2 ϩ was observed with an unexpectedly high yield 9 and with an energetic threshold at the solid ionization threshold. 10 This was attributed to a bimolecular interaction resulting from multielectron ͑multi-photon͒ excitations.…”

“…10 This was attributed to a bimolecular interaction resulting from multielectron ͑multi-photon͒ excitations. 9,10 In this work we investigate how ͑and if͒ the nature of O 2 ϩ species is related to hydrogen. Therefore, we have undertaken comparative electron stimulated desorption ͑ESD͒ studies on solid CO 2 and deliberate hydrogenated CO 2 .…”