Gas-phase thorium molecules from laser ablation

Abstract

Laser ablation is performed on an oxidized, roughly 35-year-old ²³²Th foil. The produced anionic and cationic molecules are investigated utilizing precision mass measurements by a multireflection time-of-flight mass spectrometer. Molecules with up to three thorium atoms are identified. This includes oxides Th_nO+ x containing up to 2n −1oxygenatomsandfurtherspeciesincorporating carbon or nitrogen. In addition, signals of U⁺,UO⁺, and the compound species ThUO+ 2 are found. Photoexcitation reveals selected molecules’ dissociation patterns. The experimental findings are compared to density functional theory calculations.