Isotope shift in the dielectronic recombination of three-electron ANd57+

Abstract

Isotope shifts in dielectronic recombination spectra were studied for Li-like ANd57+ ions with A=142 and A=150. From the displacement of resonance positions energy shifts δ E142,150(2s-2p1/2)= 40.2(3)(6) meV (stat)(sys)) and δ E142,150(2s-2p3/2) = 42.3(12)(20) meV of 2s-2pj transitions were deduced. An evaluation of these values within a full QED treatment yields a change in the mean-square charge radius of 142,150δ <r2> = -1.36(1)(3) fm2. The approach is conceptually new and combines the advantage of a simple atomic structure with high sensitivity to nuclear size.