14 research outputs found
Nuclear Charge Radius of Be
The nuclear charge radius of Be was precisely determined using the
technique of collinear laser spectroscopy on the transition in the Be ion. The mean square charge radius increases
from Be to Be by \delta ^{10,12} = 0.69(5) \fm^{2}
compared to \delta ^{10,11} = 0.49(5) \fm^{2} for the
one-neutron halo isotope Be. Calculations in the fermionic molecular
dynamics approach show a strong sensitivity of the charge radius to the
structure of Be. The experimental charge radius is consistent with a
breakdown of the N=8 shell closure.Comment: 5 pages, 3 figure
Collinear laser spectroscopy of atomic cadmium
Hyperfine structure and factors of the atomic 5s\,5p\,\; ^3\rm{P}_2
\rightarrow 5s\,6s\,\; ^3\rm{S}_1 transition are determined from collinear
laser spectroscopy data of Cd and Cd. Nuclear
magnetic moments and electric quadrupole moments are extracted using reference
dipole moments and calculated electric field gradients, respectively. The
hyperfine structure anomaly for isotopes with and nuclear
ground states and isomeric states is evaluated and a linear
relationship is observed for all nuclear states except . This
corresponds to the Moskowitz-Lombardi rule that was established in the mercury
region of the nuclear chart but in the case of cadmium the slope is
distinctively smaller than for mercury. In total four atomic and ionic levels
were analyzed and all of them exhibit a similar behaviour. The electric field
gradient for the atomic 5s\,5p\,\; ^3\mathrm{P}_2 level is derived from
multi-configuration Dirac-Hartree-Fock calculations in order to evaluate the
spectroscopic nuclear quadrupole moments. The results are consistent with those
obtained in an ionic transition and based on a similar calculation.Comment: 12 pages, 5 figure
Precision Test of Many-Body QED in the Be Fine Structure Doublet Using Short-Lived Isotopes
Absolute transition frequencies of the 2s\; ^2{\rm S}_{1/2} \rightarrow
2p\;^2\mathrm{P}_{1/2,3/2} transitions in Be were measured for the
isotopes Be. The fine structure splitting of the state and its
isotope dependence are extracted and compared to results of \textit{ab initio}
calculations using explicitly correlated basis functions, including
relativistic and quantum electrodynamics effects at the order of
and . Accuracy has been improved in both the theory and
experiment by 2 orders of magnitude, and good agreement is observed. This
represents one of the most accurate tests of quantum electrodynamics for
many-electron systems, being insensitive to nuclear uncertainties.Comment: 5 pages, 2 figure
Structural trends in atomic nuclei from laser spectroscopy of tin
Tin is the chemical element with the largest number of stable isotopes. Its complete proton shell, comparable with the closed electron shells in the chemically inert noble gases, is not a mere precursor to extended stability; since the protons carry the nuclear charge, their spatial arrangement also drives the nuclear electromagnetism. We report high-precision measurements of the electromagnetic moments and isomeric differences in charge radii between the lowest 1/2(+), 3/2(+), and 11/2(-) states in Sn117-131, obtained by collinear laser spectroscopy. Supported by state-of-the-art atomic-structure calculations, the data accurately show a considerable attenuation of the quadrupole moments in the closed-shell tin isotopes relative to those of cadmium, with two protons less. Linear and quadratic mass-dependent trends are observed. While microscopic density functional theory explains the global behaviour of the measured quantities, interpretation of the local patterns demands higher-fidelity modelling. Measurements of the hyperfine structure of chemical elements isotopes provide unique insight into the atomic nucleus in a nuclear model-independent way. The authors present collinear laser spectroscopy data obtained at the CERN ISOLDE and measure hyperfine splitting along a long chain of odd-mass tin isotopes.Peer reviewe
Nuclear charge radii of â¶ÂČâ»âžâ°Zn and their dependence on cross-shell proton excitations
Nuclear charge radii of â¶ÂČâ»âžâ°Zn have been determined using collinear laser spectroscopy of bunched ion beams at CERN-ISOLDE. The subtle variations of observed charge radii, both within one isotope and along the full range of neutron numbers, are found to be well described in terms of the proton
excitations across the Z = 28 shell gap, as predicted by large-scale shell model calculations. It comprehensively explains the changes in isomer-to-ground state mean square charge radii of â¶âčâ»â·âčZn, the inversion of the
odd-even staggering around N = 40 and the odd-even staggering systematics of the Zn charge radii. With two protons above Z = 28, the observed charge radii of the Zn isotopic chain show a cumulative effect of different aspects of nuclear structure including single particle structure, shell closure, correlations and deformations near the proposed doubly magic nuclei, â¶âžNi and â·âžNi
Quadrupole moments of <sup>29</sup>Mg and <sup>33</sup>Mg
The quadrupole moments of 29Mg and 33Mg have been constrained by collinear
laser spectroscopy at CERN-ISOLDE. The values are consistent with shell-model
predictions, thus supporting the current understanding of light nuclei
associated with the "island of inversion"
Precision Test of Many-Body QED in the Be+ 2p Fine Structure Doublet Using Short-Lived Isotopes
Absolute transition frequencies of the 2s S-2(1/2) -> 2p P-2(1/2,3/2) transitions in Be+ were measured for the isotopes Be-7,Be-9-12. The fine structure splitting of the 2p state and its isotope dependence are extracted and compared to results of ab initio calculations using explicitly correlated basis functions, including relativistic and quantum electrodynamics effects at the order of ma(6) and ma(7) x ln a. Accuracy has been improved in both the theory and experiment by 2 orders of magnitude, and good agreement is observed. This represents one of the most accurate tests of quantum electrodynamics for many-electron systems, being insensitive to nuclear uncertainties.5 pages, 2 figuresstatus: publishe
Hyperfine structure and nuclear magnetic moments of the praseodymium isotopes
International audienceCollinear Laser spectroscopy was applied to measure the hyperfine structure ofPr at ISOLDE/CERN. Combined with measurements of the stable isotopePr at the TRIGA-SPEC setup in Mainz we were able to determine the magnetic moments of the neutron-deficient isotopesPr,Pr andPr for the first time