$\mathit{\text{Ab}}\mathit{\text{initio}}$ 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$\pm$550 ${\text{cm}}^{-1}$ and 28587$\pm$650 ${\text{cm}}^{-1}$ for $7\text{\hspace{0.17em}⁣}{s}^{2}8s{}^2\text{\hspace{0.17em}⁣}{S}_{1\text{\hspace{0.17em}⁣}\mathrm{/}\text{\hspace{0.17em}⁣}2}$ $\to$ $7\text{\hspace{0.17em}⁣}{s}^{2}7\text{\hspace{0.17em}⁣}p{}^2\text{\hspace{0.17em}⁣}{P}_{1\text{\hspace{0.17em}⁣}\mathrm{/}\text{\hspace{0.17em}⁣}2}^o$ and $7\text{\hspace{0.17em}⁣}{s}^{2}7\text{\hspace{0.17em}⁣}d{}^2\text{\hspace{0.17em}⁣}{D}_{3\text{\hspace{0.17em}⁣}\mathrm{/}\text{\hspace{0.17em}⁣}2}$ $\to$ $7\text{\hspace{0.17em}⁣}{s}^{2}7\text{\hspace{0.17em}⁣}p{}^2\text{\hspace{0.17em}⁣}{P}_{1\text{\hspace{0.17em}⁣}\mathrm{/}\text{\hspace{0.17em}⁣}2}^o$, respectively.