$\textit{Ab initio}$ multiconfigurational calculations of experimentally significant energy levels and transition rates in Lr I $\left( Z=103 \right)$
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$\pm$550 $\text{cm}^{-1}$ and 28587$\pm$650 $\text{cm}^{-1}$ for $7\!s^2 8s~^{2} \! {S}_{1\!/\!2}$ $\rightarrow$ $7\!s^2 7\!p ~^{2} \! {P}^{o}_{1\!/\!2 }$ and $7\!s^2 7\!d ~^{2} \! {D}_{3\!/\!2 }$ $\rightarrow$ $7\!s^2 7\!p ~^{2} \! {P}^{o}_{1\!/\!2 }$, respectively.