Kinetic energy distributions for O− and metastable CO* produced by electron stimulated desorption from condensed CO2 Original Research Article

We report kinetic energy (KE) distributions of O− anions and metastable CO* produced by 10–30 eV electron stimulated desorption from multilayer CO2 films condensed on polycrystalline platinum at 20 K. The O− KE distributions are obtained from energy analysis with a hemispherical electrostatic deflector and the CO* KEs from time-of-flight measurements. Both anion and metastable energy distributions are broadened and the energy shifted is compared to those of the gas phase. The narrow (∼160 meV) and low energy (∼60 meV) peaked CO* KE distributions reveal that post-dissociation interactions play a minor role in the broadening, whereas the wide (>1 eV) KE distributions of O− result mainly from multiphonon excitation of the substrate by the departing stable fragment anion.