Description of nuclei in theA∼ 100 mass region with the interacting boson model

Abstract

Even-even nuclei in the A ∼ 100 mass region are investigated within the framework of the interacting boson model-1 (IBM-1). The study includes energy spectra and electric quadrupole transition properties of zirconium, molybdenum, ruthenium and palladium isotopes with neutron number N ≥ 52. A global parametrization of the IBM-1 Hamiltonian is found leading to a description of about 300 collective levels in 30 nuclei with a root-mean-square deviation from the observed level energies of 120 keV. The importance of the d 5/2 subshell closure at neutron number N = 56 is pointed out. The geometric character of the nuclei can be visualized by plotting the potential energy surface V (β, γ) obtained from the IBM-1 Hamiltonian in the classical limit. The parametrization established on the basis of known elements is used to predict properties of the unknown, neutron-rich isotopes 106 Zr, 112 Mo, 116 Ru and 122 Pd.

Extended interacting boson model description of Pd nuclei in the A∼100 transitional region

“…For the parametrization, a linear dependence on the fractional fillings is assumed by adding extra two nuclei to the calculation described in the previous work [6]. The energy levels of 98−100 Pd are calculated and the comparison of experimental spectra for the ground state illustrated in Fig.…”

“…Actually, the even-even Pd, Ru and Mo nuclei around the N=50 shell show the spherical behaviour according to the interacting boson model-1 (IBM-1) calculation in Ref. [6].…”

“…The structure of the even-even nuclei in the A∼100 region were studied both theoretically and experimentally during the last years [1][2][3][4][5][6][7][8][9]. The ratio of the energy of the 4 + over 2 + in the ground state band, E 4 + /E 2 + , is always used to investigste whether the nuclei are spherical or not.…”

“…The main purpose of this paper is to complete the investigations of all nuclei in the isotopic chain of Pd with Z=46 by expanding the previous work [6]. The energy levels and B(E2) values of 98,100 Pd isotopes have been calculated with refitted IBM-1 parameters and compared to new experimental results [8,9].…”

New lifetime measurements inPd109and the onset of deformation atN=60

“…Refs. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]). The precise origins and evolutions of such phenomena are still not well-understood.…”