$\textit{Ab initio}$ multiconfigurational calculations of experimentally significant energy levels and transition rates in Lr I $\left( Z=103 \right)$

TL;DR

This study performs advanced multiconfigurational calculations to accurately determine energy levels and transition rates in lawrencium (Lr I), achieving good agreement with experimental data and improving upon previous theoretical models.

Contribution

It introduces a combined single reference and multireference approach to better account for core and static correlation effects in heavy element calculations.

Findings

Reported energies for key transitions with uncertainties of about 550-650 cm^{-1}

Good agreement with recent experimental and theoretical results

Enhanced computational method for heavy element atomic structure

Abstract

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.