Electron scattering in chlorine dioxide

Cross-sections are reported for total integral and backward scattering of electrons from chlorine dioxide (OClO) for energies in the range 20-500 meV. The measurements were made in transmission experiments using a synchrotron radiation photoionization apparatus with an energy resolution in the incident electron beam of ~1.0 meV (FWHM). Integral and backward scattering cross-sections are reported. The present integral cross-section values are a correction to those reported in an earlier publication (Gulley et al 1998a J. Phys. B: At. Mol. Opt. Phys. 31 5197) which have been found to be too low due to the presence of an impurity in the original OClO samples. The absolute accuracy of the integral cross-sections is limited by experimental difficulties with respect to strong rotationally inelastic forward scattering due to the dipolar nature of the target molecules. Backward scattering data provide good evidence that dissociative attachment occurs through p-wave attachment. Comparison is made with predictions of the first Born pure dipole approximation for both total and backward scattering with excellent agreement above 100 meV with integral scattering data, but showing a significant underestimate for backward scattering cross-sections. Behaviour at energies below 100 meV represents competition between inelastic scattering and attachment and is not well understood.