Tje global dynamical correlation energies for 575 even even nuclei with proton numbers ranging from Z = 8 to Z = 108 calculated with the covariant density functional theory using the PC-PK1 parametrization are present...Tje global dynamical correlation energies for 575 even even nuclei with proton numbers ranging from Z = 8 to Z = 108 calculated with the covariant density functional theory using the PC-PK1 parametrization are presented. The dynamical correlation energies include the rotational correction energies obtained with the cranking approximation and the quadrupole vibrational correction energies. The systematic behavior of the present correlation energies is in good agreement with that obtained from the projected generator coordinate method using the SLy4 Skyrme force although our values are systematically smaller. After including the dynamical correlation energies, the root- mean-square deviation predicted by the PC-PK1 for the 575 even-even nuclei masses is reduced from 2.58 MeV to 1.24 MeV.展开更多
The rich phenomena of deformations in neutron-deficient krypton isotopes, such as shape evolution with neutron number and shape coexistence, have attracted the interest of nuclear physicists for decades. It is interes...The rich phenomena of deformations in neutron-deficient krypton isotopes, such as shape evolution with neutron number and shape coexistence, have attracted the interest of nuclear physicists for decades. It is interesting to study such shape phenomena using a novel way, e.g. by thermally exciting the nucleus. In this work, we develop the finite temperature covariant density functional theory for axially deformed nuclei with the treatment of pairing correlations by the BCS approach, and apply this approach for the study of shape evolution in 72,74Kr with increasing temperature. For 72Kr, with temperature increasing, the nucleus firstly experiences a relatively quick weakening in oblate deformation at temperature T-0.9 MeV, and then changes from oblate to spherical at T-2.1 MeV. For 74Kr, its global minimum is at quadrupole deformation β2--0.14 and abruptly changes to spherical at T-1.7 MeV. The proton pairing transition occurs at critical temperature 0.6 MeV following the rule Tc =0.6△p （0）, where △p（0） is the proton pairing gap at zero temperature. The signatures of the above pairing transition and shape changes can be found in the specific heat curve. The single-particle level evolutions with temperature are presented.展开更多
The temperature dependence of the shell corrections to the energy sEsell,entropy T8S sell,and free en-ergy oFshell is studied by employing the covariant density functional theory for closed-shell nuclei.Taking 144Sm a...The temperature dependence of the shell corrections to the energy sEsell,entropy T8S sell,and free en-ergy oFshell is studied by employing the covariant density functional theory for closed-shell nuclei.Taking 144Sm as an example,studies have shown that,unlike the widely-used exponential dependence exp(-E*/Ed),8Eshell exhibits a non-monotonous behavior,ie.,first decreasing 20%approaching a temperature of 0.8 MeV,and then fading away exponentially.Shell corrections to both free energy 8F shell and entropy T8S shell can be approximated well using the Bohr-Mottelson forms T/sinh(t)and[rcoth(r)-1]/sinh(r),respectively,in which Tx T.Further studies on the shell corrections in other closed-shell nuclei,100Sn and 208 Pb,are conducted,and the same temperature dependen-cics are obtained.展开更多
The density-dependent term in Skyrme forces is essential to simulate three-body and many-body correlations beyond the low-momentum two-body interaction. We speculate that a single density term may be insumcient and a ...The density-dependent term in Skyrme forces is essential to simulate three-body and many-body correlations beyond the low-momentum two-body interaction. We speculate that a single density term may be insumcient and a higher-order density dependent term is added. The present work investigates the influence of higher-order density dependencies based on extended UNEDF0 and SkM＊ forces. Global descriptions of nuclear masses and charge radii are presented. The extended UNEDF0 force gives a global rms error on binding energies of 1.29 MeV. The influence on fission barriers and equation of state are also investigated. Perspectives to improve Skyrme forces are discussed, including global center-of-mass corrections and Lipkin-Nogami pairing corrections.展开更多
The generalized time-dependent generator coordinate method(TD-GCM)is extended to include pairing correlations.The correlated GCM nuclear wave function is expressed in terms of time-dependent generator states and weigh...The generalized time-dependent generator coordinate method(TD-GCM)is extended to include pairing correlations.The correlated GCM nuclear wave function is expressed in terms of time-dependent generator states and weight functions.The particle–hole channel of the effective interaction is determined by a Hamiltonian derived from an energy density functional,while pairing is treated dynamically in the standard BCS approximation with time-dependent pairing tensor and single-particle occupation probabilities.With the inclusion of pairing correlations,various time-dependent phenomena in open-shell nuclei can be described more realistically.The model is applied to the description of saddle-to-scission dynamics of induced fission.The generalized TD-GCM charge yields and total kinetic energy distribution for the fission of 240Pu,are compared to those obtained using the standard time-dependent density functional theory(TD-DFT)approach,and with available data.展开更多
In the paper, we will discuss the most recent theoretical approaches developed by our group,to understand the mechanisms of decay by one proton emission, and the structure and shape of exotic nuclei at the limits of s...In the paper, we will discuss the most recent theoretical approaches developed by our group,to understand the mechanisms of decay by one proton emission, and the structure and shape of exotic nuclei at the limits of stability.展开更多
基金We acknowledge S. Goriely, B. Sun, and P. W. Zhao for stimulating discussions. This work was supported in part by the National Undergraduate Training Programs for Innovation and Entrepreneurship （Project No. 201210635132）, the National Basic Research Program of China （973 Program） （Grant No. 2013CB834400）, the National Natural Science Foundation of China （Grant Nos. 10975008, 10947013, 11175002, 11105110, 11105111, and 11205004）, the Research Fund for the Doctoral Program of Higher Education （Grant No. 20110001110087）, the Natural Science Foundation of Chongqing （Grant No. cstc2011jjA0376）, and the Fundamental Research Funds for the Central Universities （Grant Nos. XDJK2010B007 and XDJK2011B002）.
文摘Tje global dynamical correlation energies for 575 even even nuclei with proton numbers ranging from Z = 8 to Z = 108 calculated with the covariant density functional theory using the PC-PK1 parametrization are presented. The dynamical correlation energies include the rotational correction energies obtained with the cranking approximation and the quadrupole vibrational correction energies. The systematic behavior of the present correlation energies is in good agreement with that obtained from the projected generator coordinate method using the SLy4 Skyrme force although our values are systematically smaller. After including the dynamical correlation energies, the root- mean-square deviation predicted by the PC-PK1 for the 575 even-even nuclei masses is reduced from 2.58 MeV to 1.24 MeV.
基金Supported by National Natural Science Foundation of China(11105042,11305161,11505157)Open Fund of Key Laboratory of Time and Frequency Primary Standards,CASSupport from Henan Administration of Foreign Experts Affairs
文摘The rich phenomena of deformations in neutron-deficient krypton isotopes, such as shape evolution with neutron number and shape coexistence, have attracted the interest of nuclear physicists for decades. It is interesting to study such shape phenomena using a novel way, e.g. by thermally exciting the nucleus. In this work, we develop the finite temperature covariant density functional theory for axially deformed nuclei with the treatment of pairing correlations by the BCS approach, and apply this approach for the study of shape evolution in 72,74Kr with increasing temperature. For 72Kr, with temperature increasing, the nucleus firstly experiences a relatively quick weakening in oblate deformation at temperature T-0.9 MeV, and then changes from oblate to spherical at T-2.1 MeV. For 74Kr, its global minimum is at quadrupole deformation β2--0.14 and abruptly changes to spherical at T-1.7 MeV. The proton pairing transition occurs at critical temperature 0.6 MeV following the rule Tc =0.6△p （0）, where △p（0） is the proton pairing gap at zero temperature. The signatures of the above pairing transition and shape changes can be found in the specific heat curve. The single-particle level evolutions with temperature are presented.
基金Supported by Naturnal Science Foundation of Henan Province(202300410480,202300410479)the National Natural Science Foundation of China(U2032141)+1 种基金the Foundation of Fundamental Research for Young Teachers of Zhengzhou University(UC 202041041)the Physics Research and Development Program of Zheng-zhou University(324102171)。
文摘The temperature dependence of the shell corrections to the energy sEsell,entropy T8S sell,and free en-ergy oFshell is studied by employing the covariant density functional theory for closed-shell nuclei.Taking 144Sm as an example,studies have shown that,unlike the widely-used exponential dependence exp(-E*/Ed),8Eshell exhibits a non-monotonous behavior,ie.,first decreasing 20%approaching a temperature of 0.8 MeV,and then fading away exponentially.Shell corrections to both free energy 8F shell and entropy T8S shell can be approximated well using the Bohr-Mottelson forms T/sinh(t)and[rcoth(r)-1]/sinh(r),respectively,in which Tx T.Further studies on the shell corrections in other closed-shell nuclei,100Sn and 208 Pb,are conducted,and the same temperature dependen-cics are obtained.
基金Supported by National Natural Science Foundation of China(11522538)
文摘The density-dependent term in Skyrme forces is essential to simulate three-body and many-body correlations beyond the low-momentum two-body interaction. We speculate that a single density term may be insumcient and a higher-order density dependent term is added. The present work investigates the influence of higher-order density dependencies based on extended UNEDF0 and SkM＊ forces. Global descriptions of nuclear masses and charge radii are presented. The extended UNEDF0 force gives a global rms error on binding energies of 1.29 MeV. The influence on fission barriers and equation of state are also investigated. Perspectives to improve Skyrme forces are discussed, including global center-of-mass corrections and Lipkin-Nogami pairing corrections.
基金This work was supported in part by the Highend Foreign Experts Plan of China,the National Key R&D Program of China(Contract No.2018YFA0404400)the National Natural Science Foundation of China(Grant Nos.12070131001,11875075,11935003,11975031,and 12141501)+1 种基金the High-performance Computing Platform of Peking University,the QuantiXLie Centre of Excellence,a project co-financed by the Croatian Government and European Union through the European Regional Development Fund-the Competitiveness and Cohesion Operational Programme(KK.01.1.1.01.0004)the Croatian Science Foundation under the project Uncertainty quantification within the nuclear energy density framework(IP-2018-01-5987).
文摘The generalized time-dependent generator coordinate method(TD-GCM)is extended to include pairing correlations.The correlated GCM nuclear wave function is expressed in terms of time-dependent generator states and weight functions.The particle–hole channel of the effective interaction is determined by a Hamiltonian derived from an energy density functional,while pairing is treated dynamically in the standard BCS approximation with time-dependent pairing tensor and single-particle occupation probabilities.With the inclusion of pairing correlations,various time-dependent phenomena in open-shell nuclei can be described more realistically.The model is applied to the description of saddle-to-scission dynamics of induced fission.The generalized TD-GCM charge yields and total kinetic energy distribution for the fission of 240Pu,are compared to those obtained using the standard time-dependent density functional theory(TD-DFT)approach,and with available data.
文摘In the paper, we will discuss the most recent theoretical approaches developed by our group,to understand the mechanisms of decay by one proton emission, and the structure and shape of exotic nuclei at the limits of stability.
