On the hyperfine structures of the ground state(s) in the 6Li and 7Li atoms

The hyperfine structure of the ground 2(2) S-states of the three-electron atoms and ions is investigated. By using our recent numerical values for the doublet electron density at the atomic nucleus, we determine the hyperfine structure of the ground (doublet) 2(2) S-state(s) in the Li-6 and Li-7 atoms. Our predicted values (228.2058 and 803.5581 MHz, respectively) agree well with the experimental values 228.20528(8) MHz (Li-6) and 803.50404(48) MHz (Li-7 [R.G. Schlecht and D.W. McColm, Phys. Rev. 142, 11 (1966)]). The hyperfine structures of a number of lithium isotopes with short lifetimes, including Li-8, Li-9, and Li-11 atoms are also predicted. The same method is used to obtain the hyperfine structures of the three-electron Be-7(+) and Be-9(+) ions in their ground 2(2) S-states. Finally, we conclude that our approach can be generalized to describe the hyperfine structure in the triplet n (3) S-states of the four-electron atoms and ions.