Triplet states in the Be atom: bound state spectrum and hyperfine structure

TL;DR

This paper provides detailed computational analysis of the bound triplet states and hyperfine structure in the beryllium atom, including precise energy level calculations and hyperfine splittings.

Contribution

It presents highly accurate calculations of the bound triplet states and hyperfine structure levels in the four-electron Be atom, which were not previously determined with such precision.

Findings

Accurate energies for triplet S, P, D, F, G states in Be atom.

Precise hyperfine structure level energies for the 23S state.

Hyperfine splittings consistent with experimental observations.

Abstract

The bound state spectrum of low-lying triplet states in the Be atom is investigated. In particular, we perform accurate computations of various bound triplet S, P, D, F, and G states in the four-electron Be atom. For the 23S(L=0) state in the Be atom we determine the hyperfine structure and a number of bound states properties by using results of highly accurate computations. The energies of the hyperfine structure levels for this state are {\epsilon}(F=12) = -13725.927(7) MHz, {\epsilon}(F=32) = -5490.371(7) MHz and {\epsilon}(F=52) = 8235.556(7) MHz, respectively. The observed hyperfine structure splittings for the the 23S(L=0) state in the 9Be atom must be {\Delta}12 = 8235.556(7) MHz and {\Delta}23 = 13725.927(7) MHz, respectively.