Gas-phase thorium molecules from laser ablation

Laser ablation is performed on an oxidized, roughly 35-year-old <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mmultiscripts><a:mi>Th</a:mi><a:mprescripts/><a:none/><a:mn>232</a:mn></a:mmultiscripts></a:math> 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 <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:msub><b:mi>Th</b:mi><b:mi>n</b:mi></b:msub><b:msubsup><b:mi mathvariant="normal">O</b:mi><b:mi>x</b:mi><b:mo>+</b:mo></b:msubsup></b:mrow></b:math> containing up to <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mrow><d:mn>2</d:mn><d:mi>n</d:mi><d:mo>−</d:mo><d:mn>1</d:mn></d:mrow></d:math> oxygen atoms and further species incorporating carbon or nitrogen. In addition, signals of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:msup><e:mrow><e:mi mathvariant="normal">U</e:mi></e:mrow><e:mo>+</e:mo></e:msup><e:mo>,</e:mo><e:mo> </e:mo><e:msup><e:mrow><e:mi>UO</e:mi></e:mrow><e:mo>+</e:mo></e:msup></e:math>, and the compound species <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:msubsup><g:mi>ThUO</g:mi><g:mn>2</g:mn><g:mo>+</g:mo></g:msubsup></g:math> are found. Photoexcitation reveals selected molecules' dissociation patterns. The experimental findings are compared to density functional theory calculations. Published by the American Physical Society 2024