Global study of quadrupole correlation effects
Global study of quadrupole correlation effects
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DOI：
10.1103/physrevc.73.034322
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发表时间：
2005-08
影响因子：
3.1
通讯作者：
M. Bender;M. Bender;M. Bender;G. Bertsch;P. Heenen
中科院分区：
文献类型：
--
作者：
M. Bender;M. Bender;M. Bender;G. Bertsch;P. Heenen
我们讨论了所有偶偶核，从{sup 16}O到超重核的基态四极关联的结合能和均方电荷半径的系统学，这些数据是可用的。为此，我们用轴质量四极矩作为生成元坐标，用角动量和粒子数投影生成元坐标方法计算了它们的关联J=0基态，自洽平均场只受轴对称、宇称对称性和时间反转对称性的限制。计算是在一个非相对论自洽平均场模型的框架内进行的，它使用相同的Skyrme相互作用SLy4和依赖于密度的配对力来产生平均场组态并将它们混合。这些是我们研究的主要结论：(1)四极关联能在100keV到5.5 MeV之间变化。它受壳体闭合的影响，但只随质量和不对称性而略有变化。(Ii)角动量J=0的投影提供了高达约4 MeV的能量增益的主要部分；研究中的所有核，包括双幻核，都通过形变获得能量。(Iii)具有不同本征轴向变形的投影态的混合使关联能量增加了几个100keV，最高可达1.5 MeV。(4)通常情况下，A60以下的原子核的关联能大于静态形变能，而形变质量较大的原子核的静态形变能大于关联能。(V)纳入四极关联能改进了对质量系统学的描述，特别是在壳层闭合附近，以及对微分量的描述，即两核子分离能和两核子能隙。关联能提供了“相互增强的磁性”的解释。(Vi)关联能降低了魔数附近结合能的壳层效应，但抑制的幅度不足以解释平均场模型中N=82和N=126中子壳闭合时的相对过结合现象。(Vii)电荷半径对四极关联也很敏感。静态四极形变使电荷半径的整体系统性有了显著的改善。动力学关联改善了半径的局部系统学，特别是在壳闭合周围。虽然动力学关联可能会减少特定原子核的电荷半径，但当包括在内时，它们会导致半径的整体增加，特别是在轻核中。
We discuss the systematics of ground-state quadrupole correlations of binding energies and mean-square charge radii for all even-even nuclei, from {sup 16}O up to the superheavies, for which data are available. To that aim we calculate their correlated J=0 ground state by means of the angular-momentum and particle-number projected generator coordinate method, using the axial mass quadrupole moment as the generator coordinate and self-consistent mean-field states restricted only by axial, parity, and time-reversal symmetries. The calculation is performed within the framework of a nonrelativistic self-consistent mean-field model by use of the same Skyrme interaction SLy4 and to a density-dependent pairing force to generate the mean-field configurations and to mix them. These are the main conclusions of our study: (i) The quadrupole correlation energy varies between a few 100 keV and about 5.5 MeV. It is affected by shell closures, but varies only slightly with mass and asymmetry. (ii) Projection on angular momentum J=0 provides the major part of the energy gain of up to about 4 MeV; all nuclei in the study, including doubly magic ones, gain energy by deformation. (iii) The mixing of projected states with different intrinsic axial deformations adds a few 100 keV up to 1.5 MeVmore » to the correlation energy. (iv) Typically nuclei below mass A{<=}60 have a larger correlation energy than static deformation energy whereas the heavier deformed nuclei have larger static deformation energy than correlation energy. (v) Inclusion of the quadrupole correlation energy improves the description of mass systematics, particularly around shell closures, and of differential quantities, namely two-nucleon separation energies and two-nucleon gaps. The correlation energy provides an explanation of 'mutually enhanced magicity'. (vi) The correlation energy tends to decrease the shell effect on binding energies around magic numbers, but the magnitude of the suppression is not large enough to explain the relative overbinding at N=82 and N=126 neutron-shell closures in mean-field models. (vii) Charge radii are also found to be sensitive to the quadrupole correlations. Static quadrupole deformations lead to a significant improvement of the overall systematics of charge radii. The dynamical correlations improve the local systematics of radii, in particular around shell closures. Although the dynamical correlations might reduce the charge radii for specific nuclei, they lead to an overall increase of radii when included, in particular in light nuclei.« less