Gas-phase thorium molecules from laser ablation

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 ThnO+x containing up to 2n - 1 oxygen atoms and further species incorporating 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.