Ab initio multiconfigurational calculations of experimentally significant energy levels and transition rates in Lr I ( Z=103 )

Large-scale multiconfigurational calculations are conducted on experimentally significant transitions in Lr I and its lanthanide homologue Lu I, exhibiting good agreement with recent theoretical and experimental results. A single reference calculation is performed, allowing for substitutions from the core within a sufficiently large active set to effectively capture the influence of the core on the valence shells, improving upon previous multiconfigurational calculations. An additional calculation utilising a multireference set is performed to account for static correlation effects which contribute to the wavefunction. Reported energies for the two selected transitions are 20716±550 cm⁻¹ and 28587±650 cm⁻¹ for 7\!s² 8s~² \! S1\!/\!2 → 7\!s² 7\!p ~² \! Pᵒ1\!/\!2 and 7\!s² 7\!d ~² \! D3\!/\!2 → 7\!s² 7\!p ~² \! Pᵒ1\!/\!2, respectively.