Toward Calculations with Spectroscopic Accuracy: the 2s2.2p 2Po_{3/2} - 2s2p2 4P_{5/2} Excitation Energy in Boron

TL;DR

This paper presents highly accurate theoretical calculations of excitation energies for boron, improving upon previous extrapolated values by incorporating relativistic and finite mass effects using a novel computational method.

Contribution

The study introduces a new partitioned correlation function interaction (PCFI) method that accurately predicts excitation energies including relativistic and mass corrections for boron.

Findings

Calculated excitation energy for B I is 28959 +/- 5 cm^{-1}.

Results agree better with some experimental estimates than previous extrapolations.

Method validated on C II levels, demonstrating broader applicability.

Abstract

No lines have been observed for transitions between the doublet and quartet levels of B I. Consequently, energy levels based on observation for the latter are obtained through extrapolation of wavelengths along the iso-electronic sequence for the 2s2.2p 2Po_{3/2} - 2s2p2 4P_{5/2} transition. In this paper, accurate theoretical excitation energies from a newly developed partitioned correlation function interaction (PCFI) method are reported for B I that include both relativistic effects in the Breit-Pauli approximation and a finite mass correction. Results are compared with extrapolated values from observed data. For B I our estimate of the excitation energy, 28959 +/- 5 cm^{-1}, is in better agreement with the values obtained by Edl\'en et al. (1969) than those reported by Kramida and Ryabtsev (2007). Our method is validated by applying the same procedure to the separation of these levels in C II