Mechanism of aqualuminescence in alkaline luminol

The paper presents the emission spectra of (i) chemiluminescence of alkaline luminol due to its oxidation by hydrogen peroxide and ferricyanide and (ii) aqualuminescence or the emission during the dissolution of γ-irradiated alkali halides in the same solution. Earlier workers attributed both these emissions to the formation of aminophthalate ion in the excited state due to oxidation by hydrogen peroxide. The present study, based on the emission spectra of chemiluminescence and aqualuminescence, suggests a simpler mechanism for the latter in which hydrogen peroxide is not involved. This is further supported by the measurement of N2 gas evolved during aqualuminescence and the electronic spectra of alkaline luminol recorded before and after the addition of the irradiated salt. (author)