Bulg. J. Phys. vol.48 no.5-6 (2021), pp. 634-644



Single-Particle Spectra, Pairing Correlations and Spectroscopic Properties of Actinide and Heavier Nuclei

P. Quentin1, L. Bonneau1, N. Minkov2, D. Ivanova3, J. Bartel4, H. Molique4, Meng-Hock Koh5
1CENBG, UMR5797, Université de Bordeaux, CNRS, 33170 Gradignan, France
2Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Tzarigrad Road 72, BG-1784 Sofia, Bulgaria
3Military Medical Academy, Sofia, Bulgaria and University Hospital "Saint Ekaterina"', Sofia, Bulgaria
4IPHC, UMR7178, Université de Strasbourg, CNRS, 67200 Strasbourg, France
5Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Malaysia
Abstract. We discuss the relevance of the single-particle (sp) properties of the well studied Skyrme SIII interaction to describe some spectroscopic properties of heavy nuclei within self-consistent Hartree-Fock plus BCS calculations (with blocking when needed), using a simple seniority pairing residual interaction (Vres). To fit Vres we took stock of the excellent consistency found in the rare-earth region between its adjustment to both moments of inertia (MoI) of well-deformed nuclei and odd-even mass differences. For simplicity reasons we thus made a fit on MoI. Our sample of nuclei was defined by all even-even isotopes of actinide and heavier elements, with two criteria: i) be well and rigidly deformed in their ground states, as assessed by a ratio E(41+)/E(21+) > 3.2, ii) present some isomeric activity with suggested isomeric energy (EIS) and spin/parity characterization. We have thus considered 14 actinide isotopes (from Uranium to Nobelium) plus 256Rf. With a simple law of variation of the pairing matrix elements according to N or Z, we get a fair reproduction of MoI except around the neutron number N = 152 where SIII exaggerates its well documented magicity (for normally deformed solutions). Such a study of MoI assesses thus also the sp spectra, of which a further evaluation of the quality is provided by the comparison of the corresponding experimental and theoretical EIS. Our calculations were limited to quasi-particle (uncoupled) configuration of the seniority 2 type. Preliminary results on some isomeric states of the considered isotopes will be discussed particularly by comparing them with those obtained in a particle number conserving approach.

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