Energies, Fine Structures, and Hyperfine Structures of the 1𝑠²2𝑠𝑛𝑝³𝑃(𝑛=2−4) States for the Beryllium Atom

Table 3

The hyperfine structure parameters (in a.u.) and coupling constants (in MHz) of the 1𝑠²2𝑠2𝑝³𝑃 state for the beryllium atom.

Method	𝑎𝑐	𝑎sd	𝑎𝑙	𝑏𝑞	𝐴2	𝐴1	Reference
LC MBPT^a	9.2319	−0.06490	0.30478	−0.1156	−124.21		[5, 6]
HF + SDCI^b	9.2738	−0.06656	0.30014	−0.1097	−124.76	−139.77	[7]
FE MCHF^c	9.2349	−0.06564	0.30261	−0.1150			[8]
MCHF	9.2416	−0.06587	0.30329	−0.11570	−124.50	−139.35	[9]
This work	9.2436	−0.06523	0.30201	−0.11588	−124.51	−139.36
Experiment					−124.5368	−139.373	[10]

^aLinked-cluster many-body perturbation theory.
^bHartree-Fock and CI allowing all SD excitations to correlation orbitals of Slater type.
^cFinite-element multiconfiguration Hartree-Fock.