Theoretical hyperfine splittings of ^7,9Be²⁺ ions for future studies of nuclear properties

The hyperfine structures of the 2 S-3(1) and 2 P-3(J) states of Be-7(2+) and Be-9(2+) are investigated within the framework of the nonrelativistic quantum electrodynamics, including relativistic and radiative corrections up to order m alpha(6). The uncertainties of the calculated hyperfine splittings are on the order of tens of ppm, and for Be-9(2+) our results improve the previous theoretical and experimental values by at least two orders of magnitude. The improved sensitivity of the hyperfine splittings of Be-7,9(2+) to the nuclear Zemach radius and electric quadrupole moment opens the way to future measurements to extract the atomic physics values of these two nuclear properties to an accuracy of 5% or better.