Transient species produced in irradiated alkaline aqueous solutions containing oxygen

The spectra and decay kinetics of the optical absorption in the UV region and at 430nm (maximum of the ozonide ion absorption), were investigated in oxygenated neutral, slightly and strongly alkaline aqueous solutions. It is assumed that the initial absorption after the pulse in oxygenated alkaline solutions is due to the ozonide ion O3-, superoxide radical ion O2- and ozone O3. The long-living absorption in these solutions cannot be excluded as to be probably caused by the ozone O3 or some product formed from O2- or an alkaline stabilized form of this radical-ion. The advantage of applying additional non-optical measurements of the system is shown on the example of H2O2 role played in the mechanism. (author)