Nobelium energy levels and hyperfine-structure constants

Advances in laser spectroscopy of superheavy (Z > 100) elements enabled determination of the nuclear moments of the heaviest nuclear which required high-precision atomic calculations of the relevant hyperfine-structure (hfs) constants. Here, we calculated the hfs constants and energy levels for a number of nobelium (Z = 102) states using a hybrid approach combining linearized coupled-cluster and configuration interaction methods. We also carried out an extensive study of the No energies using the 16-electro configuration interaction method to determine the position of the 5f(13)7s(2)6d and 5f(13)7s(2)7p levels with a hole in the 5 f shell to evaluate their potential effect on the hyperfine-structure calculations of the low-lying 5f(14)7s6d and 5f(14)7s7p levels. We find that unlike the case of Yb, the mixing of the low-lying levels with filled and unfilled f shells is small and does not significantly influence their properties. The resulting hfs constants for the 5f(14)7s7p P-1(1)0 level, combined with laser-spectroscopy measurement, were used to extract nobelium nuclear properties.