Kinetic energy distributions for O − and metastable CO * produced by electron stimulated desorption from condensed CO 2

Abstract

We report kinetic energy (KE) distributions of O − anions and metastable CO * produced by 10–30 eV electron stimulated desorption from multilayer CO 2 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.