Theoretical study on the reaction mechanism of Sc atoms with carbon dioxide

B3LYP and CCSD(T) calculations with various basis sets show that the Sc+CO2→ScO+CO reaction can proceed by two distinct pathways, Sc+CO2→(η1-O)ScOCO→(η2-O,O)cyc-ScCO2→ScO+CO→ end-/side-OScCO with the largest barrier of 3.2 kcal/mol and barrier-less Sc+CO2→(η2-C,O)(ScOC)O→end-OScCO→ScO+CO. The `end-onʹ OScCO complex bound by 7.2 kcal/mol relative to ScO+CO is predicted to be the dominant reaction product. The reaction is more than 30 kcal/mol exothermic and the Sc atom is expected to be efficient in reforming CO2 to carbon monoxide.