Formation of superoxo species by interaction of O(2) with Na atoms deposited on MgO powders: a combined continuous-wave EPR (CW-EPR), hyperfine sublevel correlation (HYSCORE) and DFT study.

The formation of O(2) (-) radical anions by contact of O(2) molecules with a Na pre-covered MgO surface is studied by a combined EPR and quantum chemical approach. Na atoms deposited on polycrystalline MgO samples are brought into contact with O(2). The typical EPR signal of isolated Na atoms disappears when the reaction with O(2) takes place and new paramagnetic species are observed, which are attributed to different surface-stabilised O(2) (-) radicals.

The reactivity of CO2 with K atoms adsorbed on MgO powders.

In this combined quantum chemical and EPR study we have investigated the formation of CO(2)(-) radicals by contact of CO(2) molecules with a K precovered MgO surface. K atoms have been deposited on polycrystalline MgO samples, and then exposed to CO(2). The typical EPR signal of the isolated K atoms disappears when the reaction with CO(2) takes place and a new paramagnetic species attributed to CO(2)(-) is observed.