0000000000515284
AUTHOR
M Avgoulea
Collinear laser spectroscopy of neutron-rich cerium isotopes near theN= 88 shape transition
Laser spectroscopy has been used to measure the isotope shifts of 146Ce and 148Ce relative to 144Ce, Z = 58. The new data, in combination with existing optical data on the stable isotopes and radioactive 144Ce isotope, permits a study of charge radii variations for the even-N Ce nuclei from N = 78 to N = 90. This range covers both the N = 82 shell closure and the N = 88 shape transition region. A marked increase in deformation occurs at N = 88 for elements with Z ≥ 60 but not for those with Z ≤ 56. The new data for Ce (Z = 58) show an intermediate behaviour, resulting in a smooth increase in deformation with Z in the N = 88, 90 region.
The shape transition in the neutron-rich yttrium isotopes and isomers
Abstract Laser spectroscopy has been used to study 86–90,92–102Y and isomeric states of 87–90,93,96,97,98Y. Nuclear charge radii differences, magnetic dipole and electric quadrupole moments have been obtained. Information on the nature of the Z ≈ 40 , N ≈ 60 sudden onset of deformation has been derived from all three parameters. It is seen that with increasing neutron number from the N = 50 shell closure that the nuclear deformation becomes increasingly oblate and increasingly soft. At N = 60 a transition to a strongly deformed rigid prolate shape occurs but prior to this, although the nuclear deformation is increasing with N, a proportionate increase in softness is also observed.
On the decrease in charge radii of multi-quasi particle isomers
Abstract We report changes in mean-square charge radii, δ 〈 r 2 〉 , magnetic moments and quadrupole moments for three multi-quasi particle isomers; 97m2Y, 176mYb and 178m1Hf. All the isomers are observed to display a decrease in 〈 r 2 〉 compared to the lower-lying nuclear state on which the isomer is built. The decreases in 〈 r 2 〉 occur despite the isomers showing increases in quadrupole moment. Possible mechanisms for the effect, which is now seen for six multi-quasi particle isomers, are discussed.
Nuclear charge radii and electromagnetic moments of radioactive scandium isotopes and isomers
International audience; Collinear laser spectroscopy experiments with the Sc + transition 3d4s 3 D 2 → 3d4p 3 F 3 at λ = 363.1 nm were performed on the 42−46 Sc isotopic chain using an ion guide isotope separator with a cooler-buncher. Nuclear magnetic dipole and electric quadrupole moments as well as isotope shifts were determined from the hyperfine structure for five ground states and two isomers. Extensive multi-configurational Dirac-Fock calculations were performed in order to evaluate the specific mass-shift, M SMS, and field-shift, F, parameters which allowed evaluation of the charge radii trend of the Sc isotopic sequence. The charge radii obtained show systematics more like the Ti r…