IONIC FRAGMENTATION AND ION-PAIR FORMATION IN CHLORINE DIOXIDE

Ionic fragmentation and ion-pair formation in chlorine dioxide (OClO) are reported. Photoionization efficiency curves of OClO+, ClO+, O-2(+), Cl+, O+, as well as of O- and Cl- are measured in the energy regime between 10 eV and 21 eV using monochromatized synchrotron radiation. Appearance potentials are obtained from photoionization efficiency curves which are used to derive photofragmentation mechanisms. These include the formation of electronically excited fragments as well as multiparticle formation. The occurrence of O-2(+) is interpreted as evidence for rearrangement processes of the chlorine dioxide cation prior to dissociation. This finding is compared to photofragmentation of electronically excited neutral OClO. Ion-pair formation of photoexcited OClO leads to formation of O- and Cl-. The importance of highly excited Rydberg states and direct processes leading to ion-pair formation is discussed.