Lyoluminescence dosimetry part I. Principles

The Role of Singlet Oxygen in the Lyoluminescence of Saccharides

“…The spectra of both mannose and fructose exhibit peaks at 385 nm, 490 nm, 535 nm, where Ettinger and Puite [4] observed only a broad band. These emission peaks may be attributed, in accordance to Khan and Kasha [16] In order to check whether this collisional oxygen emission process is accompanied even by the concurring carbonyl emission, the emission spectrum of mannose was measured at low oxygen concentration as well (Figure 8).…”

“…Referring to Vassil'ev's [3] model for the chemiluminescence of hydrocarbons, Ettinger and Puite [4] proposed the following description for the mechanism of the LLprocess: Radicals are formed in the solid by radiation absorption and oxidized to peroxyl radicals during dissolution. By disproportionation these peroxyl radicals yield a carbonyl compound, an oxygen molecule, and an alcohol fragment.…”

“…Ettinger and Puite [4] explained lyoluminescence in Russel's [7] model. This model deals in general with the disproportionation of a peroxyl radical and the distribution of its excitation energy to the resulting molecules.…”

“…The LL of amino acids exhibits a similar single broad emission band in the range 450-490 nm [4,9], so the LL is described with the relaxation of an excited carbonyl compound. The LL of saccharides, in contrast, consist of a spectrum composed by several peaks and in general stretches towards longer wavelengths, well beyond 600 nm.…”

“…It is supported by the fact that the LL-intensity of saccharides increases with increasing oxygen concentration of solvent in the range 1.5-15 mg/1 0 2 [1]. The LL of amino acids, in contrast, decreases with increasing oxygen concentration [4]. Therefore the LL of amino acids cannot be described in the same way.…”