Novel ultraviolet product spectra in the photolysis of chlorine dioxide

U.v. absorption spectra have been recorded during the low-intensity photolysis of chlorine dioxide, OClO, using a diode-array spectrometer. A broad-band u.v. spectrum was observed which was favoured by low temperature and high OClO pressure. The absorption could be explained only in part by the presence of ClO dimer, Cl2O2. Unequivocal assignment of the residual spectrum was not possible but it may be due to the chlorine perchlorate molecule, ClOClO3, a recently discovered product of OClO photolysis.