Isotope Shift in the Dielectronic Recombination of Three-ElectronNd57+A

Abstract

Isotope shifts in dielectronic recombination spectra were studied for Li-like A Nd 57+ ions with A=142 and A=150. From the displacement of resonance positions energy shifts δE 142,150 (2s − 2p 1/2 ) = 40.2(3)(6) meV ((stat)(sys)) and δE 142,150 (2s − 2p 3/2 ) = 42.3(12)(20) meV of 2s − 2p j transitions were deduced. An evaluation of these values within a full QED treatment yields a change in the mean-square charge radius of 142,150 δ r 2 = -1.36(1)(3) fm 2 . The approach is conceptually new and combines the advantage of a simple atomic structure with high sensitivity to nuclear size.

Major role of multielectronicK-Lintershell resonant recombination processes in Li- to O-like ions of Ar, Fe, and Kr

“…The ion is then left in a (usually) doubly-excited state which can decay radiatively, completing the DR process. Extended experimental and theoretical investigations on DR with highly charged ions (HCI) have been carried out in recent years by various groups (e. g. [3][4][5][6][7][8]). Usually, DR is described in an independent-particle model, only taking into account the interaction between the two electrons involved -the initially free one and an active bound one.…”

Isotope shifts in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations

“…The development of experimental techniques allowing the accurate measurement of line IS enhances the need for accurate calculations of the relevant electronic parameters that account for both electron correlation and relativistic effects, especially for medium and heavy openshell atoms [21,22]. Amongst these techniques, the storage ring measurement of isotope shifts in the spectrum of resonant electron-ion recombination of heavy few-electron ions gives access to nuclear charge radii changes involving heavy stable and unstable nuclides, as demonstrated for three-electron Nd 57+ isotopes produced at GSIs storage ring ESR [8]. Dielectronic recombination (DR) measurements have also been performed at the heavy-ion storage ring TSR in Heidelberg for Be-, B-and C-like ions relevant to astrophysics and plasma physics [23,24], although no IS in the DR spectra have been reported so far.…”

“…In this framework, Kozlov et al [6] proposed a method to exclude systematic effects caused by changes in the isotope abundances during the evolution of the universe, but there is a need to develop methods that can accurately estimate isotope shifts [7]. Isotope shifts of spectral lines are also used in nuclear physics to estimate the root-mean-square nuclear charge radii and mean-square radii changes δ r 2 A,A ′ for which the electronic factors play a crucial role (see for example [8][9][10][11][12]). …”

Overlapping resonances in nuclei coupling to the atomic shells

“…For magnetic multipole transitions, the magnetic Hamiltonian in Eq. (27) can be written using the multipole expansion as…”

“…In the resonant process of DC, a free electron recombines into a HCI with the simultaneous excitation of a bound electron, which leaves a hole in the previously occupied bound shell. DC followed by x-ray decay of the excited electrons is known as dielectronic recombination (DR), an atomic physics process which is used in high-precision experiments with HCI to measure isotope shifts and provide complementary data to nuclear radii obtained via other methods [27]. The hole created by DC can be occupied via electronic decay that occurs simultaneously with the excitation of the nucleus, i.e., NEET.…”