The Role of Singlet Oxygen in the Lyoluminescence of Saccharides

Lyoluminescence, the radiation induced light emission during the dissolution of irradiated solid substances like alkali halides, saccharides, amino acids etc. was proposed as a method of dosimetry. It is established that lyoluminescence is a consequence of a reaction of radicals from radiolysis with oxygen dissolved in the solvent. The role of oxygen in the lyoluminescence of saccharides has been investigated. It has been proved that oxygen is not only necessary for the chemical reaction preceeding the lyoluminescence process, but that it is also the emission centre itself. Singlet oxygen is released from the disproportionation of peroxyl radicals produced during solution. The lyoluminescence emission peaks may be attributed to the simultaneous transitions [ 1Σ g+ ] [ 1Σ g+ ] , [ 1Δg ] [1 Δg ] and [1Σg+] [ 1Δg ] to [3Σg+] [3Σg-] of collisional pairs of singlet oxygen molecules