The α-cluster structures for 12^C and 16^O are investigated in the framework of the covariant density functional theory, where the pairing correlation is treated with a particle number conserving shell-model-like app...The α-cluster structures for 12^C and 16^O are investigated in the framework of the covariant density functional theory, where the pairing correlation is treated with a particle number conserving shell-model-like approach. The ground states of 12^C and 160 have been calculated and the density distributions demonstrate an equilateral triangle 3α clustering for 12^C and a regular tetrahedron 4α clustering for 16^O The existence of linear nα chain structure of both 12^C and 16^O is revealed at high quadrupole deformation.展开更多
The tensor force and pairing correlation effects on the two-proton radioactivity of^(18)Mg and^(20)Si with a pronounced two-proton halo are explored in the framework of spherical Skyrme-Hartree-Fock-Bogoliubov theory....The tensor force and pairing correlation effects on the two-proton radioactivity of^(18)Mg and^(20)Si with a pronounced two-proton halo are explored in the framework of spherical Skyrme-Hartree-Fock-Bogoliubov theory.It is shown that the halo sizes are enhanced with the increase in the strength of the tensor force and pairing correlation.Furthermore,the increasing halo sizes lead to the enhancement of diproton emission.Then,the tensor force is found to have a small influence on the two-proton decay energies,and the two-proton decay energies calculated with strong surface pairing are smaller than those with weak mixed pairing.Because the two-proton decay energies are relat-ively large,the predicted order of magnitude of half-lives within the effective liquid drop model is not sensitive to the decay energy variation caused by the tensor force and pairing correlation,which has a value of approximately 10^(-18)s.展开更多
In this contribution I would like to review briefly our recent studies on nuclear α formation probabilities in heavy nuclei and their indication on the underlying structure of the nuclei involved.In particular, I wil...In this contribution I would like to review briefly our recent studies on nuclear α formation probabilities in heavy nuclei and their indication on the underlying structure of the nuclei involved.In particular, I will show that the empirical α-formation probabilities, which can be extracted from experimental half-lives, exhibit a rather smooth function with changing proton or neutron numbers. This allows us to distinguish the role played by pairing collectivity in the clustering process. The sudden hindrance of the clustering of the nucleons around the N = 126 shell closure is due to the fact that the configuration space does not allow a proper manifestation of the pairing collectivity. The influence of the Z = 82 shell closure on the α formation properties will also be discussed. Moreover, we have evaluated the α-decay fine structure to excited 0+states in Hg and Rn isotopes as well as the α-decay from the excited 0+states in the mother nucleus. It is thus found that the α decay is sensitive to the mixture of configurations corresponding to different nuclear shapes.展开更多
The effects of pairing correlation in Yb isotopes are investigated by covariant density functional theory with pairing correlations and blocking effects treated exactly by a shell model like approach （SLAP）. Experim...The effects of pairing correlation in Yb isotopes are investigated by covariant density functional theory with pairing correlations and blocking effects treated exactly by a shell model like approach （SLAP）. Experimental one- and two-neutron separation energies are reproduced quite well. The traditional BCS calculations always give larger pairing energies than those given by SLAP calculations, particularly for the nuclei near the proton and neutron drip lines. This may be caused because many of the single particle orbits above the Fermi surface are involved in the BCS calculations, but many of them are excluded in the SLAP calculations.展开更多
Some special issues of the random phase approximation(RPA) in the relativistic approach are reviewed. A full consistency and proper treatment of coupling to the continuum are responsible for the successful application...Some special issues of the random phase approximation(RPA) in the relativistic approach are reviewed. A full consistency and proper treatment of coupling to the continuum are responsible for the successful application of the RPA in the description of dynamical properties of finite nuclei. The fully consistent relativistic RPA(RRPA) requires that the relativistic mean filed (RMF) wave function of the nucleus and the RRPA correlations are calculated in a same effective Lagrangian and the consistent treatment of the Dirac sea of negative energy states. The proper treatment of the single particle continuum with scattering asymptotic conditions in the RMF and RRPA is discussed. The full continuum spectrum can be described by the single particle Green's function and the relativistic continuum RPA is established. A separable form of the paring force is introduced in the relativistic quasi-particle RPA.展开更多
A fixed particle number BCS （FBCS） approach is formulated in the relativistic mean field （RMF） model. It is shown that the RMF＋FBCS model obtained can describe the weak pairing limit. We calculate the ground-stat...A fixed particle number BCS （FBCS） approach is formulated in the relativistic mean field （RMF） model. It is shown that the RMF＋FBCS model obtained can describe the weak pairing limit. We calculate the ground-state properties of the calcium isotopes ＆32-74Ca and compare the results with those obtained from the usual RMF＋BCS model. Although the results are quite similar to each other, we observe the interesting phenomenon that for ^54Ca, the FBCS approach can enhance the occupation probability of the 2p1/2 single particle level and slightly increases its radius, compared with the RMF＋BCS model. This leads to the unusual scenario that although ^54Ca is more bound with a spherical configuration, the corresponding size is not the most compact. We anticipate that such a phenomenon might happen for other neutron-rich nuclei and should be checked by further more systematic studies.展开更多
Ground state properties for Mg isotopes, including binding energies, one- and two-neutron separation energies, pairing energies, nuclear matter radii and quadrupole deformation parameters, are obtained from the self- ...Ground state properties for Mg isotopes, including binding energies, one- and two-neutron separation energies, pairing energies, nuclear matter radii and quadrupole deformation parameters, are obtained from the self- consistent relativistic mean field （RMF） model with the pairing correlations treated by a shell-mode-like approach （SLAP）, in which the particle-number is conserved and the blocking effects are treated exactly. The experimental data, including the binding energies and the one- and two-neutron separation energies, which are sensitive to the treatment of pairing correlations and block effects, are well reproduced by the RMF＋SLAP calculations.展开更多
In this work, the effects of the pairing correlation on the properties of neutron drops N=6-50 trapped in a harmonic oscillator potential with ω = 10 Me V are investigated by comparing the results given by the Skyrme...In this work, the effects of the pairing correlation on the properties of neutron drops N=6-50 trapped in a harmonic oscillator potential with ω = 10 Me V are investigated by comparing the results given by the Skyrme Hartree-Fock and Hartree-FockBogoliubov theories with the density-dependent delta interaction(DDDI) pairing force. The results showed that the pairing correlation slightly made the neutron drops more bound, and increased the central neutron density, the spin-orbit and pseudo spin-orbit splittings. Thus, the pairing correlation must be accounted for to improve the Skyrme functional compared with the ab initio calculations. Furthermore, although the single-particle energy gaps with or without pairing were similar, the shell closures varied due to pair scattering. Here, the shell closures in neutron drops using the Sk M* parameter set and DDDI pairing force were found at N=8, 16, and 32.展开更多
In this work,we have performed Skyrme density functional theory(DFT)calculations of nuclei around^132Sn to study whether the abnormal odd-even staggering(OES)behavior of binding energies around N=82 can be reproduced....In this work,we have performed Skyrme density functional theory(DFT)calculations of nuclei around^132Sn to study whether the abnormal odd-even staggering(OES)behavior of binding energies around N=82 can be reproduced.With the Skyrme forces SLy4 and SkM*,we tested the volume-and surface-type pairing forces and also the intermediate between these two pairing forces,in the Hartree-Fock-Bogoliubov(HFB)approximation with or without the Lipkin-Nogami(LN)approximation or particle number projection after the convergence of HFBLN(PLN).The Universal Nuclear Energy Density Function(UNEDF)parameter sets are also used.The trend of the neutron OES against the neutron number or proton number does not change significantly by tuning the density dependence of the pairing force.Moreover,for the pairing force that is favored more at the nuclear surface,a larger mass OES is obtained,and vice versa.It appears that the combination of volume and surface pairing can give better agreement with the data.In the studies of the OES,a larger ratio of surface to volume pairing might be favored.Additionally,in most cases,the OES given by the HFBLN approximation agrees more closely with the experimental data.We found that both the Skyrme and pairing forces can influence the OES behavior.The mass OES calculated by the UNEDF DFT is explicitly smaller than the experimental one.The UNEDF1 and UNEDF2 forces can reproduce the experimental trend of the abnormal OES around^132Sn.The neutron OES of the tin isotopes given by the SkM*force agrees more closely with the experimental one than that given by the SLy4 force in most cases.Both SLy4 and SkM*DFT have difficulties in reproducing the abnormal OES around^132Sn.Using the PLN method,the systematics of OES are improved for several combinations of Skyrme and pairing forces.展开更多
基金Supported by Major State Basic Research Development (973) Program (2007CB815000)NSFC (11175002,11105005)Research Fund for the Doctoral Program of Higher Education (20110001110087)
文摘The α-cluster structures for 12^C and 16^O are investigated in the framework of the covariant density functional theory, where the pairing correlation is treated with a particle number conserving shell-model-like approach. The ground states of 12^C and 160 have been calculated and the density distributions demonstrate an equilateral triangle 3α clustering for 12^C and a regular tetrahedron 4α clustering for 16^O The existence of linear nα chain structure of both 12^C and 16^O is revealed at high quadrupole deformation.
基金Supported by the National Natural Science Foundation of China(U1832120,11675265)the Natural Science Foundation for Outstanding Young Scholars of Hebei Province,China(A2020210012)+4 种基金the Natural Science Foundation of Hebei Province,China(A2021210010)the Key Laboratory of High Precision Nuclear Spectroscopy,Institute of Modern Physics,Chinese Academy of Sciences(IMPKFKT2021002)the Graduate Student Innovative Research Project of Shijiazhuang Tiedao University(YC2022062)the Continuous Basic Scientific Research Project(WDJC-2019-13)the Leading Innovation Project(LC 192209000701).
文摘The tensor force and pairing correlation effects on the two-proton radioactivity of^(18)Mg and^(20)Si with a pronounced two-proton halo are explored in the framework of spherical Skyrme-Hartree-Fock-Bogoliubov theory.It is shown that the halo sizes are enhanced with the increase in the strength of the tensor force and pairing correlation.Furthermore,the increasing halo sizes lead to the enhancement of diproton emission.Then,the tensor force is found to have a small influence on the two-proton decay energies,and the two-proton decay energies calculated with strong surface pairing are smaller than those with weak mixed pairing.Because the two-proton decay energies are relat-ively large,the predicted order of magnitude of half-lives within the effective liquid drop model is not sensitive to the decay energy variation caused by the tensor force and pairing correlation,which has a value of approximately 10^(-18)s.
基金Swedish Research Council(VR)(621-2012-3805,621-2013-4323)Gran Gustafsson Foundation
文摘In this contribution I would like to review briefly our recent studies on nuclear α formation probabilities in heavy nuclei and their indication on the underlying structure of the nuclei involved.In particular, I will show that the empirical α-formation probabilities, which can be extracted from experimental half-lives, exhibit a rather smooth function with changing proton or neutron numbers. This allows us to distinguish the role played by pairing collectivity in the clustering process. The sudden hindrance of the clustering of the nucleons around the N = 126 shell closure is due to the fact that the configuration space does not allow a proper manifestation of the pairing collectivity. The influence of the Z = 82 shell closure on the α formation properties will also be discussed. Moreover, we have evaluated the α-decay fine structure to excited 0+states in Hg and Rn isotopes as well as the α-decay from the excited 0+states in the mother nucleus. It is thus found that the α decay is sensitive to the mixture of configurations corresponding to different nuclear shapes.
基金Supported by"the Fundamental Research Funds for the Central Universities"(JUSRP1035)NSFC(11305077,11335002)
文摘The effects of pairing correlation in Yb isotopes are investigated by covariant density functional theory with pairing correlations and blocking effects treated exactly by a shell model like approach （SLAP）. Experimental one- and two-neutron separation energies are reproduced quite well. The traditional BCS calculations always give larger pairing energies than those given by SLAP calculations, particularly for the nuclei near the proton and neutron drip lines. This may be caused because many of the single particle orbits above the Fermi surface are involved in the BCS calculations, but many of them are excluded in the SLAP calculations.
基金National Natural Science Foundation of China(10775183,10535010)Major State Basic Research Development Programme of China(2007CB815000)
文摘Some special issues of the random phase approximation(RPA) in the relativistic approach are reviewed. A full consistency and proper treatment of coupling to the continuum are responsible for the successful application of the RPA in the description of dynamical properties of finite nuclei. The fully consistent relativistic RPA(RRPA) requires that the relativistic mean filed (RMF) wave function of the nucleus and the RRPA correlations are calculated in a same effective Lagrangian and the consistent treatment of the Dirac sea of negative energy states. The proper treatment of the single particle continuum with scattering asymptotic conditions in the RMF and RRPA is discussed. The full continuum spectrum can be described by the single particle Green's function and the relativistic continuum RPA is established. A separable form of the paring force is introduced in the relativistic quasi-particle RPA.
基金Supported by the National Natural Science Foundation of China(11522539,11735003,11775014,11375022)
文摘A fixed particle number BCS （FBCS） approach is formulated in the relativistic mean field （RMF） model. It is shown that the RMF＋FBCS model obtained can describe the weak pairing limit. We calculate the ground-state properties of the calcium isotopes ＆32-74Ca and compare the results with those obtained from the usual RMF＋BCS model. Although the results are quite similar to each other, we observe the interesting phenomenon that for ^54Ca, the FBCS approach can enhance the occupation probability of the 2p1/2 single particle level and slightly increases its radius, compared with the RMF＋BCS model. This leads to the unusual scenario that although ^54Ca is more bound with a spherical configuration, the corresponding size is not the most compact. We anticipate that such a phenomenon might happen for other neutron-rich nuclei and should be checked by further more systematic studies.
基金Supported by NSFC(11465001,11275098,11275248,11505058,11165001)Natural Science Foundation of Inner Mongolia of China(2016BS0102)
文摘Ground state properties for Mg isotopes, including binding energies, one- and two-neutron separation energies, pairing energies, nuclear matter radii and quadrupole deformation parameters, are obtained from the self- consistent relativistic mean field （RMF） model with the pairing correlations treated by a shell-mode-like approach （SLAP）, in which the particle-number is conserved and the blocking effects are treated exactly. The experimental data, including the binding energies and the one- and two-neutron separation energies, which are sensitive to the treatment of pairing correlations and block effects, are well reproduced by the RMF＋SLAP calculations.
基金the National Natural Science Foundation of China(Grant Nos.11405116,and 11775119).
文摘In this work, the effects of the pairing correlation on the properties of neutron drops N=6-50 trapped in a harmonic oscillator potential with ω = 10 Me V are investigated by comparing the results given by the Skyrme Hartree-Fock and Hartree-FockBogoliubov theories with the density-dependent delta interaction(DDDI) pairing force. The results showed that the pairing correlation slightly made the neutron drops more bound, and increased the central neutron density, the spin-orbit and pseudo spin-orbit splittings. Thus, the pairing correlation must be accounted for to improve the Skyrme functional compared with the ab initio calculations. Furthermore, although the single-particle energy gaps with or without pairing were similar, the shell closures varied due to pair scattering. Here, the shell closures in neutron drops using the Sk M* parameter set and DDDI pairing force were found at N=8, 16, and 32.
基金Supported by National Natural Science Foundation of China(U1732138,11505056,11605054,11975209,11790325,11947410,11847315)the Outstanding Young Talent Research Fund of Zhengzhou University(152137002)。
文摘In this work,we have performed Skyrme density functional theory(DFT)calculations of nuclei around^132Sn to study whether the abnormal odd-even staggering(OES)behavior of binding energies around N=82 can be reproduced.With the Skyrme forces SLy4 and SkM*,we tested the volume-and surface-type pairing forces and also the intermediate between these two pairing forces,in the Hartree-Fock-Bogoliubov(HFB)approximation with or without the Lipkin-Nogami(LN)approximation or particle number projection after the convergence of HFBLN(PLN).The Universal Nuclear Energy Density Function(UNEDF)parameter sets are also used.The trend of the neutron OES against the neutron number or proton number does not change significantly by tuning the density dependence of the pairing force.Moreover,for the pairing force that is favored more at the nuclear surface,a larger mass OES is obtained,and vice versa.It appears that the combination of volume and surface pairing can give better agreement with the data.In the studies of the OES,a larger ratio of surface to volume pairing might be favored.Additionally,in most cases,the OES given by the HFBLN approximation agrees more closely with the experimental data.We found that both the Skyrme and pairing forces can influence the OES behavior.The mass OES calculated by the UNEDF DFT is explicitly smaller than the experimental one.The UNEDF1 and UNEDF2 forces can reproduce the experimental trend of the abnormal OES around^132Sn.The neutron OES of the tin isotopes given by the SkM*force agrees more closely with the experimental one than that given by the SLy4 force in most cases.Both SLy4 and SkM*DFT have difficulties in reproducing the abnormal OES around^132Sn.Using the PLN method,the systematics of OES are improved for several combinations of Skyrme and pairing forces.
