Spectra of barium, radium, and element 120; application of the combined correlation potential, singles-doubles, and configuration interaction ab initio method

TL;DR

This paper presents an advanced ab initio computational approach combining multiple methods to accurately predict the spectra of heavy alkaline earth elements, including element 120, with QED corrections, achieving unprecedented agreement with experimental data.

Contribution

The paper introduces a novel combined computational method that improves spectral predictions for heavy elements, including the superheavy element 120, with inclusion of QED effects.

Findings

Unprecedented agreement between theory and experiment for barium and radium spectra.

Accurate predictions for missing and unreliable data for all three elements.

Successful application of the combined method to superheavy element 120.

Abstract

We apply a version of the recently developed approach combining the correlation potential, linearized singles-doubles coupled-cluster, and the configuration interaction methods to the spectra of the heavy alkaline earths barium, radium, and element 120. Quantum electrodynamics radiative corrections are included. We have found unprecedented agreement between ab initio theory and experiment for the spectra of barium and radium, and we make accurate predictions for missing and unreliable data for all three atoms.