Showing papers by "Chong Qi published in 2014"
TL;DR: In this article, the authors show that the empirical coefficients that appear in the Geiger-Nuttall (GN) law have a deep physical meaning, and that the GN law is successful within the restricted experimental data sets available so far, but is not valid in general.
47 citations
TL;DR: In this paper, the effect of the reduction of the effective interaction on the structure and decay properties of loosely bound proton-rich nuclei around $A=20$ is investigated within the framework of the nuclear shell model.
Abstract: The properties of loosely bound proton-rich nuclei around $A=20$ are investigated within the framework of the nuclear shell model. In these nuclei, the strength of the effective interactions involving the loosely bound proton ${s}_{1/2}$ orbit is significantly reduced in comparison with that of those in their mirror nuclei. We evaluate the reduction of the effective interaction by calculating the monopole-based-universal interaction (${V}_{\mathrm{MU}}$) in the Woods-Saxon basis. The shell-model Hamiltonian in the $sd$ shell, such as USD, can thus be modified to reproduce the binding energies and energy levels of the weakly bound proton-rich nuclei around $A=20$. The effect of the reduction of the effective interaction on the structure and decay properties of these nuclei is also discussed.
31 citations
Royal Institute of Technology1, French Alternative Energies and Atomic Energy Commission2, University of York3, Uppsala University4, University of Valencia5, Hungarian Academy of Sciences6, University of Debrecen7, University of Warsaw8, Warsaw University of Technology9, University of Padua10, Ankara University11, Middle East Technical University12, Osaka University13
TL;DR: In this article, linear polarization and angular correlations of gamma-rays depopulating excited states in the neutron-deficient nucleus Ru-94(44)50 have been measured, enabling firm spin-parity assignments for several excited states.
Abstract: Linear polarization and angular correlations of gamma-rays depopulating excited states in the neutron-deficient nucleus Ru-94(44)50 have been measured, enabling firm spin-parity assignments for several excited states in this nucleus. The deduced multipolarities of strong transitions in the yrast structure were found to be mostly of stretched M1, E1, and E2 types and, in most cases, in agreement with previous tentative assignments. The deduced multipolarity of the 1869 keV and the connecting 257 and 1641 keV transitions indicates that the state at 6358 keV excitation energy has spin parity 12(1)(-) rather than 12(3)(+) as proposed in previous works. The presence of a 12(1)(-) state is interpreted within the framework of large-scale shell-model calculations as a pure proton-hole state dominated by the pi(p(1/2)(-1)circle times g(9/2)(-5)) and pi(p(3/2)(-1) g(9/2)(-5)) configurations. A new positive-parity state is observed at 6103 keV and is tentatively assigned as 12(2)(+). The 14(1)(-) state proposed earlier is reassigned as 13(4)(-) and is interpreted as being dominated by neutron particle-hole core excitations. The strengths of several E1 transitions have been measured and are found to provide a signature of core-excited configurations.
14 citations
TL;DR: In this article, the alpha-decay fine structure to excited 0(2+) states in Hg and Rn isotopes was analyzed. And the authors also investigated alpha decay from the excited state P(0(2)(+)) in the parent nucleus by evaluating the corresponding hindrance factor (HF).
Abstract: We analyze the alpha-decay fine structure to excited 0(2)(+) states in Hg and Rn isotopes. These states are described as minima in the potential energy surface (PES) provided by the standard deformed Woods-Saxon plus pairing approach. We also investigate alpha decay from the excited state P(0(2)(+)) in the parent nucleus by evaluating the corresponding hindrance factor (HF). By analyzing the experimental HF's we find the remarkable property that the ground and excited states D(0(1)(+)) and D(0(2)(+)) in the daughter nuclei are occupied with almost equal probabilities if there is no excited P(0(+)) states in the parent nucleus. Moreover, if there exists an excited state P(0(2)(+)) then the occupation probability of this state is 25%.
12 citations
TL;DR: In this article, the magnetic moments of the first excited 2(+) state in even-even nuclei Sn102-130 and the low-lying yrast states in odd-mass nuclei SN-101-109,Sn-123-131 are calculated within the framework of the nucleon-pair approximation (NPA) of the shell model, by using the standard multipole-multipole interaction.
Abstract: The magnetic moments of the first excited 2(+) state in even-even nuclei Sn102-130 and the low-lying yrast states in odd-mass nuclei Sn-101-109,Sn-123-131 are calculated within the framework of the nucleon-pair approximation (NPA) of the shell model, by using the standard multipole-multipole interaction. Our calculations agree reasonably well with available experimental data. The g(2(1)(+)) values, as well as the contributions from their spin and orbital angular momentum components, are evaluated in terms of the small NPA subspace spanned by S and D nucleon pairs. The magnetic moment is suggested to be a sensitive probe of the nuclear wave function in this region.
11 citations
TL;DR: In this article, the correlated basis is constructed with the eigenvectors of the Hamiltonian that is diagonalized in each partition of the shell model, and a truncation scheme is established by naturally taking the low-lying correlated-basis vectors in different partitions.
Abstract: We present a basis selection method for truncated shell-model calculations. In this method, the correlated basis is constructed with the eigenvectors of the Hamiltonian that is diagonalized in each partition of the shell model. A truncation scheme is established by naturally taking the low-lying correlated-basis vectors in different partitions, which is equivalent to the $jj$-coupling scheme of the shell model when all the correlated-basis vectors are considered. The results are compared with standard shell-model calculations. The convergence properties of the correlated-basis method are discussed.
8 citations
Royal Institute of Technology1, Uppsala University2, Hungarian Academy of Sciences3, University of Debrecen4, University of York5, University of Warsaw6, Osaka University7, Middle East Technical University8, University of Valencia9, Warsaw University of Technology10, University of Padua11, Ankara University12
TL;DR: The neutron-deficient semimagic (n = 50) Rh-95 nucleus has been produced at high spins using the projectile-target system Ca-40 + Ni-58 at 125 MeV beam energy as discussed by the authors.
Abstract: The neutron-deficient semimagic (neutron number N = 50) Rh-95 nucleus has been produced at high spins using the projectile-target system Ca-40 + Ni-58 at 125 MeV beam energy. The gamma-decays of le ...
5 citations
Journal Article•
TL;DR: In this paper, the authors introduced the framework of shell model and its application in nuclei, and used the nuclear shell model to study properties of selected nuclei in psd region, a new effective shell-model Hamiltonian is introduced.
Abstract: Background: Nuclear shell model is widely applied in the studies of light and medium-mass nuclei. The ground and excited state energies, electromagnetic properties and β decay properties of these nuclei can be well understood by solving many body Schrodinger equation with effective shell-model Hamiltonian in the model space. Purpose: The aim is to introduce the framework of shell model and its application in nuclei. Methods: The nuclear shell model is used to study properties of selected nuclei. Results: In psd region, a new effective shell-model Hamiltonian is introduced. The neutron drip-line of C, N, and O isotopes can be given with such Hamiltonian. The nuclei around A=20 with weakly bound proton are investigated through a modified shell model Hamiltonian. N=Z nucleus is good for studying the effect of proton-neutron pair. 46V and 50Mn have both T=0 and 1 rotational band. 92Pd can be understood under a spin alignment isoscalar scheme of proton-neutron pair. Mirror nuclei around N=Z in fp region can be used for the investigation of charge symmetry breaking effect of nuclear force. Conclusion: Nuclear shell model is proper and useful for the description of light and medium-mass nuclei.