ESR KINETIC-STUDY OF THE PHOTOBLEACHING OF CHLORINE DIOXIDE SOLUTIONSAT 303, 365 AND 436 NM

Initial quantum yields for the photobleaching of OClO dissolved in CCl 4 at 298 K are measured by electron spin resonance spectrometry at thr ee wavelengths, under 1 atm of either N2 or O2. Yields are unaffected at 365 nm, but increase by about 45% at 303 and 436 nm, when O2 is rep laced by N2. These results, at variance with gas-phase photolysis, sug gest a qualitative change in the mechanism of photofragmentation at al most-equal-to 365 nm. We show that OClO solvatochromic shifts are cont rolled by the dynamic polarization of the medium, rather than by a mod ification of the energies of the states involved.