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. A ppearance potentials are obtained from photoionization efficiency curv es which are used to derive photofragmentation mechanisms. These inclu de the formation of electronically excited fragments as well as multip article formation. The occurrence of O-2(+) is interpreted as evidence for rearrangement processes of the chlorine dioxide cation prior to d issociation. This finding is compared to photofragmentation of electro nically excited neutral OClO. Ion-pair formation of photoexcited OClO leads to formation of O- and Cl-. The importance of highly excited Ryd berg states and direct processes leading to ion-pair formation is disc ussed.