Binding of oxygen with titanium dioxide on singlet potential energy surface: An ab initio investigation

Ab initio calculations have been carried out to investigate interaction of titanium dioxide TiO 2 with oxygen O 2 in ground triplet and excited singlet states. On a singlet potential energy surface (PES) formation of a stable compound of titanium peroxide TiO 4 is revealed which should appear in reaction of TiO 2 with singlet oxygen without activation barrier. This peroxide is lower in energy than the ground state of two individual molecules TiO 2 + 3O 2 by 34.6 kcal/mol. Location of conical intersection between triplet and singlet PESs of TiO 2 O 2 is also investigated.