Interaction of reactive ions with Pt(100). II. Dissociative scattering of molecular ions near the threshold energy region

Dissociative scattering of N+2, CO+, and CO+2 ions from Pt(100) has been studied at low energies. For dissociated N+ emergence, the threshold of incident kinetic energy was found to be 40 eV. The threshold of dissociated CO+ emergence in the CO+2 incidence was clearly observed at 25 eV. The threshold of dissociated C+ emergence in the CO+ incidence was observed at 70 eV. Correlation between the dissociation energy of a free molecule and the threshold of incident kinetic energy is clearly discernible. The angular distributions show that the dissociation product appears at larger scattering angles than that for the parent molecular ions scattered nondissociatively. These experimental results are consistent with the model that dissociation is due to translational-rovibrational energy transfer above the dissociation limit at the impulse collision with the surface.