Low-energy dissociation of OClO following electron capture

We have studied negative ion formation following low-energy electron impact (0-10 eV) to OClO including a time-of-flight analysis of the ions. The dominant feature is formation of a transient negative ion (OClO-*) by resonant electron capture in the vicinity of 6.7 eV which decomposes into Cl-, O-, ClO- and O-2(-). The total dissociative attachment (DA) cross section at the resonance maximum (0.7 eV) is near 10(-15) cm(2) with ClO-+O the dominant channel. Although the DA reaction O-2 + Cl- is exothermic by nearly 4 eV the Cl- ion appears with a mean kinetic energy of only 0.4+/-0.1 eV indicating effective vibrational excitation of neutral O-2. Also observed at higher target gas pressures is the parent anion ClO2- which arises from an effective charge transfer process involving a metastable complex formed in the collision between the dominant DA product ClO- and the sample molecule OClO. Possible implications of these results for the heterogeneous chemistry of OClO on polar stratospheric cloud particles are considered.