A new rotational band has been identified and assigned to 188Au for the first time using the 173Yb(19F,4nγ) reaction at the beam energies of 86 and 90 MeV. This band is proposed to be built on the πh9/2 νi13/2 configuration by comparing the band properties with known bands in neighboring nuclei. The prolate-to-oblate shape transition through triaxial shape has been proposed to occur around 188Au for the πh9/2 νi13/2 bands in odd-odd Au isotopes on the basis of total Routhian surface (TRS) calculations.
OSHIMA MTOH YKOIZUMI MKIMURA AHatsukawa YMORIKAWA TNAKAMURA MSUGAWARE MKUSAKARI H
Theoretical calculations have been performed for the ν9/2+[624](i13/2) and ν7/2-[503](f7/2) bands of 185Pt in the framework of particle-rotor model. The band properties of signature splitting and configuration mixing have been analyzed. The level energy and signature splitting before the band crossing can be well interpreted by introducing triaxiality. The positive-parity yrast band is pro posed to be dominated by the ν9/2+[624](i13/2) component, while the negative-parity band shows strong mixing of ν7/2-[503](f7/2) and ν9/2-[505](h9/2) configurations.
LI GuangShun1,2, ZHOU XiaoHong1,2, ZHANG ShuangQuan3, ZHANG YuHu1 & MENG Jie3 1 Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
The charge form factors of elastic electron scattering for isotones with N=20 and N=28 are calculated using the phase-shift analysis method,with corresponding charge density distributions from relativistic mean-field theory.The results show that there are sharp variations at the inner parts of charge distributions with the proton number decreasing.The corresponding charge form factors are divided into two groups because of the unique properties of the s-states wave functions,though the proton numbers change uniformly in two isotonic chains.Meanwhile,the shift regularities of theminima are also discussed,and we give a clear relation between theminima of the charge form factors and the corresponding charge radii.This relation is caused by the diffraction effect of the electron.Under this conclusion,we calculate the charge density distributions and the charge form factors of the A=44 nuclei chain.The results are also useful for studying the central depression in light exotic nuclei.
It has been found that high-order deformation (e.g.β6) can have important effects on the structures of superheavy nuclei. In the present work, we investigate octupole deformation effects on superheavy nuclei with an improved potential-energy-surface (PES) calculation by including reflection-asymmetric deformations in a space of (β2 ,β3 ,β4 , β5). The calculations give various deformations including highly deformed (β2 ≈ 0.4) and superdeformed (β2 ≈ 0.7) shapes. The octupole-deformation degree of freedom mainly affects the fission barrier beyond the second minimum of PES.
In this paper,we include the density dependence behavior of the symmetry energy in the improved quark mass density dependent (IQMDD) model.Under the mean field approximation,this model is applied to investigate neutron star matter and neutron stars successfully.Effects of the density dependence of the symmetry energy on neutron stars are described.
Total-Routhian-Surface calculations have been performed to investigate the deformation and align-ment properties of the No isotopes. It is found that normal deformed and superdeformed states in these nuclei can coexist at low excitation energies. In neutron-deficient No isotopes, the superdeformed shapes can even become the ground states. Moreover, we plotted the kinematic moments of inertia of the No isotopes, which follow very nicely available experimental data. It is noted that, as the rotational frequency increases, align-ments develop at hω =0.2-0.3 MeV. Our calculations show that the occupation of the νj15/2 orbital plays an important role in the alignments of the No isotopes.
We investigate the half-lives of β + /EC(electron capture) decay using the proton-neutron quasiparticle random-phase approximation(pnQRPA) with a δ-form Gamow-Teller residual interaction.Both particle-hole and particle-particle residual interactions are consistently introduced in dealing with the pnQRPA matrix equation.The sensitivity of the calculated half-lives to some physical quantities used in the calculations is examined.Calculations are performed for even-even neutron-deficient isotopes ranging from Z = 10 to Z = 76.Good agreement between experiment and theory is achieved especially for the nuclei far from stability,and the results of our calculations are discussed with comparison with other theoretical results.Predictions on the β-decay half-lives of some very neutron-deficient nuclei are also given for reference in future experiments.
Very neutron-deficient nuclei are investigated with Woods-Saxon potentials,especially the newly measured A =2Z-1 nucleus ^(65)As [X.L.Tu et al.,Phys.Rev.Lett.106,112501(2011)],where the experimental proton separation energy is obtained as-90(85) keV for the first time.Careful consideration is given to quasibound protons with outgoing Coulomb wave boundary conditions.The observed proton halos in the first excited state of ^(17)F and in the ground states of ^(26,27,28)P are reproduced well,and predictions of proton halos are made for the ground states of ^(56,57)Cu and ^(65)As.The sensitivity of the results to the proton separation energy is discussed in detail,together with the effect of the l=1 centrifugal barrier on proton halos.
In the present research, we used the 17Ne beam at 30.8 MeV/u to bombard the 43mg/cm2 12C target and measured the angular correlations between the fragments and emitted proton. In the break-up reaction of 17Ne, one-proton knockout would result in an unstable nu-cleus 16F, which would further decay by the proton emission. The measured angular correlation between the 16F momentum and the relative momentum of its decay products was compared with theoretical calculations and indicated that the valence proton in 17Ne has the most probability to be situated in the s1/2 orbital with a small admixture of the d5/2 orbital. The present results suggest that 17Ne has a halo structure.