Atomic data benchmarked by Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Beryllium

TL;DR

This paper uses advanced relativistic atomic structure calculations to provide highly accurate data on beryllium's energy levels, transition rates, and hyperfine constants, validating the methods against experimental data and offering valuable data for astrophysical applications.

Contribution

The study presents comprehensive MCDHF/RCI calculations for beryllium, achieving high accuracy and agreement with experimental data, and estimates uncertainties for transition rates.

Findings

Average difference with experimental energies is 0.011%.

Oscillator strengths agree within 2% for most transitions.

Results support reliable predictions for unmeasured states.

Abstract

The multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction (RCI) methods are used to provide excitation energies, radiative transition data, lifetimes, Lande g-factors, hyperfine interaction constants and isotope shift parameters for the 99 lowest levels of configurations 1s^22snl (n <= 7) + 1s^22p^2 in beryllium. Compared with available experimental excitation energies, the average difference with the standard deviation is 7.08 +/- 1.14cm^-1 (0.011% +/- 0.003%), which demonstrates the excellent theory-observation agreement. The uncertainties of the transition rates are estimated based on two independent methods. The present MCDHF/RCI oscillator strengths and those obtained from the explicitly correlated Gaussian (ECG) method all agree within 2%, except for four transitions affected by strong cancellation effects. For lifetimes, hyperfine splittings and isotope shifts, the present MCDHF/RCI results show good agreement with the few available experimental values, supporting the reliability of our predictions for many states lacking experimental measurements. These comprehensive results can be used in line identification and diagnostics of astrophysical plasmas.