Large-scale shell-model calculations on the spectroscopy ofN<126Pb isotopes

Abstract

Large-scale shell-model calculations are carried out in the model space including neutron-hole orbitals 2p 1/2 , 1f 5/2 , 2p 3/2 , 0i 13/2 , 1f 7/2 and 0h 9/2 to study the structure and electromagnetic properties of neutron deficient Pb isotopes. An optimized effective interaction is used. Good agreement between full shell-model calculations and experimental data is obtained for the spherical states in isotopes 194−206 Pb. The lighter isotopes are calculated with an importance-truncation approach constructed based on the monopole Hamiltonian. The full shell-model results also agree well with our generalized seniority and nucleon-pair-approximation truncation calculations. The deviations between theory and experiment concerning the excitation energies and electromagnetic properties of low-lying 0 + and 2 + excited states and isomeric states may provide a constraint on our understanding of nuclear deformation and intruder configuration in this region.

Shell model description of heavy nuclei and abnormal collective motions

“…We have done a systematic calculation on the structure and electromagnetic transition properties of neutrondeficient Pb isotopes, which may be studied experimentally using the AGATA detector. Our shell-model calculations can reproduce well the excitation energies of the low-lying 0 + and 2 + states in isotopes 198−206 Pb [3]. The overall agreement between experiments and calculations are quite satisfactory.…”

“…We have optimized the monopole channel of the effective Hamiltonians for describing the Sn and Pb isotopes, which work well also for most open-shell nuclei. We consider single-particle orbitals g 07/2 , 1d 5/2,3/2 , 2s 1/2 and 0h 11/2 (simply denoted as gdsh) for our studies of nuclei above 100 Sn [2] and the six orbitals between N = 82 and 126, 0h 9/2 , 1 f 7/2,5/2 , 2p 3/2,1/2 and 0i 13/2 (denoted as hfpi) for our studies of neutron-deficient Pb isotopes [3]. But it should be pointed out that the motivation is not to fit data better but to get a better wave function and more reliable predictions on unknowns.…”

Description of the critical point symmetry in 124 Te by IBM-2

“…It is well known that the low-lying yrast states in other Te isotopes such as 112,114 Te show the similar behavior, i.e., typical vibrational like spectra but the other properties deviate from vibrator [6,[66][67][68]. All these Te isotopes locate around the midshell 118 Te.…”

Evidence for octupole collectivity in $$^{172}{\mathrm {Pt}}$$

“…Proton-proton and neutron-neutron interactions were taken from Refs. [46,47]. The cross-shell neutron-proton interactions were taken from the charge-dependent Bonn nucleonnucleon potential with slight modifications in order to better reproduce the properties of the N = 84 isotones [48].…”