CHARGE-EXCHANGE OF SWIFT MOLECULES H-2(+), H-2, CO2+ AND CO2, AT PD(111) SURFACES

Molecular ions and neutral molecules are scattered at 500 eV and at grazing incidence from metal surfaces. H-2(+) and CO2+ are subject to charge exchange processes which lead in part to dissociation. In the case of CO2 evidence for negative molecular ion formation is found. Potassium ''poisons'' the dissociation of H-2 on Pd. These findings are supported by comparison of different metals, Pd(111) and Pd(111) covered with a monolayer of K. The dissociation probability of H-2(+) and H-2(0) decreases at the K-covered surface, in the case of CO2+ and CO20 an increase is found. CO2+ on Pd(111) + K dissociates completely.