Determination of the spectral dependences of the absolute quantum yields of O(1S) by the XeO* luminescence method. I. Photolysis of CO2and N2O

Abstract

A method is proposed for measuring the spectral distribution of the absolute quantum yield of O(1S) in the photolysis of oxygen-containing compounds (RO). This involves investigating the luminescence excitation spectra of XeO* excimers formed in the O(1S)+Xe+XeXeO*+Xe reaction. The measurements were made in a following RO?Xe mixture of accurately known composition in a system with differential evacuation. The spectral dependences of the quantum yield of O(1S) in the photolysis of N2O (?=170?102 nm) and CO2 (?=128?102 nm) were obtained. The absorption spectra of these compounds and the excitation spectra of RO, corresponding to the transitions to states which dissociated forming O(1S), were determined. The mechanism for excitation and dissociation of CO2 and N2O in these spectral ranges was discussed in the light of the experimental results and the published data. Transfer of the excitation energy from the Xe atoms, formed by absorption of radiation in the spectral range ? < 120 nm, to N2O molecules was observed, resulting in the dissociation of N2O to give and O(1S) or in the formation of N2 and XeO*.