Formation and Characterization of ZrO3 and HfO3 Molecules in Solid Argon

ZrO3 and HfO3 molecules were prepared via reactions of metal monoxides with dioxygen in solid argon and were characterized using matrix isolation infrared absorption spectroscopy as well as theoretical calculations. Unlike the titanium monoxide molecule. which reacted spontaneously with dioxygen to form TiO3, the ZrO and HfO molecules reacted with to give the ZrO3 and HfO3 molecules only under visible light irradiation. Density functional calculations predicted that both the ZrO3 and HfO3 molecules possess a closed-shell singlet ground state with a non-planar C-s geometry, in which the side-on coordinated O-2 falls into the peroxide category.