Author(s)
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Manea, V (CSNSM, Orsay ; Heidelberg, Max Planck Inst.) ; Ascher, P (Heidelberg, Max Planck Inst.) ; Atanasov, D (Heidelberg, Max Planck Inst.) ; Barzakh, A E (St. Petersburg, INP) ; Beck, D (Darmstadt, GSI) ; Blaum, K (Heidelberg, Max Planck Inst.) ; Borgmann, Ch (Heidelberg, Max Planck Inst.) ; Breitenfeldt, M (Leuven U.) ; Cakirli, R B (Heidelberg, Max Planck Inst.) ; Cocolios, T E (Manchester U.) ; Day Goodacre, T (Manchester U. ; CERN ; Gottingen U.) ; Fedorov, D V (St. Petersburg, INP) ; Fedosseev, V N (CERN ; Gottingen U.) ; George, S (Heidelberg, Max Planck Inst.) ; Herfurth, F (Darmstadt, GSI) ; Kowalska, M (CERN) ; Kreim, S (Heidelberg, Max Planck Inst. ; CERN) ; Litvinov, Yu A (Darmstadt, GSI) ; Lunney, D (CSNSM, Orsay) ; Marsh, B (CERN ; Gottingen U.) ; Neidherr, D (Darmstadt, GSI) ; Rosenbusch, M (Greifswald U.) ; Rossel, R E (CERN ; Gottingen U. ; Mainz U., Inst. Phys.) ; Rothe, S (CERN ; Gottingen U. ; Mainz U., Inst. Phys.) ; Schweikhard, L (Greifswald U.) ; Wienholtz, F (Greifswald U.) ; Wolf, R N (Greifswald U.) ; Zuber, K (Dresden, Tech. U.) |
Abstract
| We present a study of nuclear shape coexistence in the region of neutron-deficient lead isotopes. The midshell gold isotopes Au180,185,188,190 (Z=79), the two long-lived nuclear states in At197 (Z=85), and the neutron-rich nuclide At219 were produced by the ISOLDE facility at CERN and their masses were determined with the high-precision Penning-trap mass spectrometer ISOLTRAP. The studied gold isotopes address the trend of binding energies in a region of the nuclear chart where the nuclear charge radii show pronounced discontinuities. Significant deviations from the atomic-mass evaluation were found for Au188,190. The new trend of two-neutron separation energies is smoother, although it does reveal the onset of deformation. The origin of this effect is interpreted in connection to the odd-even staggering of binding energies, as well as theoretically by Hartree-Fock-Bogoliubov calculations including quasiparticle blocking. The role of blocking for reproducing the large odd-even staggering of charge radii in the mercury isotopic chain is illustrated. |