Laser Spectroscopy of Neutron-Rich 207,208Hg Isotopes: Illuminating the Kink and Odd-Even Staggering in Charge Radii across the N = 126 Shell Closure

Lars Ghys, A.V. Afanasjev, Thomas Day Goodacre, Anatoly (A.E.) Barzakh, Anatoly (A.E.) Barzakh, Bruce A Marsh, Simon Sels, P. Ring, Andrei N. Andreyev, Piet Van Duppen, Numa A. Althubiti, Boris Andel, Dimitar Atanasov

Research outputpeer-review


The mean-square charge radii of 207;208Hg (Z ¼ 80, N ¼ 127, 128) have been studied for the first time and those of 202;203;206Hg (N ¼ 122, 123, 126) remeasured by the application of in-source resonance-ionization laser spectroscopy at ISOLDE (CERN). The characteristic kink in the charge radii at the
N = 126 neutron shell closure has been revealed, providing the first information on its behavior below the Z = 82 proton shell closure. A theoretical analysis has been performed within relativistic Hartree-Bogoliubov and nonrelativistic Hartree-Fock-Bogoliubov approaches, considering both the new mercury
results and existing lead data. Contrary to previous interpretations, it is demonstrated that both the kink at N ¼ 126 and the odd-even staggering (OES) in its vicinity can be described predominately at the meanfield level and that pairing does not need to play a crucial role in their origin. A new OES mechanism is suggested, related to the staggering in the occupation of the different neutron orbitals in odd- and even-A nuclei, facilitated by particle-vibration coupling for odd-A nuclei.
Original languageEnglish
Article number032502
Pages (from-to)1-7
Number of pages7
JournalPhysical review Letters
Issue number3
StatePublished - 22 Jan 2021

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