Isotope shifts in 20,22Ne: Precision measurements and global analysis in the framework of intermediate coupling

We report precision measurements of the Ne-20-Ne-22 isotope shift for several transitions, as well as state-of-the-art, ab initio field-shift calculations. Our results are combined with historical measurements in a global fit to obtain the isotope shifts of all 50 low-lying neon levels with high precision. These level shifts show a wealth of electronic, nuclear, and relativistic phenomena. Relying on the analogy between mass shift and fine-structure operators, we explain this plethora of neon level shifts utilizing a small number of effective parameters in a global parametric investigation. This investigation provides a birds-eye view on the isotope shift phenomena in noble gasses. From this vantage point, we reinterpret every effort made to calculate neon mass shifts ab initio and show that a remarkable agreement between experiment and theory is obtained.