共查询到20条相似文献,搜索用时 296 毫秒
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利用同位旋依赖的尼尔逊势,在宏观-微观理论框架下,计算了幻数N=28同中子链上原子核的性质,研究了N=28同中子链上原子核的形变和形状共存现象. 研究结果表明,N=28这个幻数在Na,Mg, Al同位素链上有着强的形状共存现象. 此外,计算表明42Si的基态为扁椭球,同时在Si同位素链上的形状共存现象相对较弱.
关键词:
同位旋
幻数
形变
形状共存 相似文献
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基于中子分离能的分析 ,Ozawa等提出丰中子轻核存在新幻数 N=1 6.对 N=1 6同中子素进行了形变和球形的相对论平均场计算 .相对论平均场的数值结果表明N=1 6同中子素有形状相变.这是一些丰中子核新幻数出现的可能原因. Based on the analysis of neutron-separation energies, Ozawa et al proposed a new magic number N =16 in light neutron-rich nuclei. The deformed and spherical relativistic mean-field(RMF) calculations have been carried out for N =16 isotones. The numerical relativistic mean-field results show there is a shape transition in N =16 isotones. This is the possible cause of the appearance of the new magic number in someneutron-rich nuclei. 相似文献
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在相对论平均场理论的框架下,对Rn同位素链原子核的结合能、形变、同位素位移等若干基态性质进行了较详细的研究.结果表明,理论计算结果与已有的实验数据符合较好.原子核的四极形变主要出现在远离幻数的区域(N=110-124和N=129-142).而在中子数大于幻数的区域(N=127-142),十六级形变也非常明显.对电荷半径的研究显示,Rn同位素链的同位素位移曲线的斜率在中子幻数处出现明显的变化.
关键词:
相对论平均场理论
电荷半径
同位素位移
单粒子能级 相似文献
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提出了一种从理论上检验壳效应的方法. 即在考虑了BCS近似的相对论平均场理论框架内, 通过计算粒子数的涨落, 发现涨落的大小和核的壳结构有紧密的关系, 由此从理论上证明了在滴线附近的丰中子区, 传统幻数N=28已经消失. 相似文献
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We study the proton magic O, Ca, Ni, Zr, Sn, and Pb isotope chains from the proton drip line to the neutron drip line with
the relativistic continuum Hartree-Bogoliubov (RCHB) theory. Particulary, we study in detail the properties of even-even Ca
isotopes due to the appearance of giant halos in neutron rich Ca nuclei near the neutron drip line. The RCHB theory is able
to reproduce the experimental binding energiesE
b and two neutron separation energiesS
2n very well. The predicted neutron drip line nuclei are28O,72Ca,98Ni,136Zr,176Sn, and266Pb. Halo and giant halo properties predicted in Ca isotopes withA>60 are investigated in detail through analysis of two neutron separation energies, nucleon density distributions, single
particle energy levels, and the occupation probabilities of energy levels including continuum states. The spin-orbit splitting
and the diffuseness of nuclear potential in these Ca isotopes, as well as the neighboring lighter isotopes in the drip line
Ca region and find certain possibilities of giant halo nuclei in the Ne−Na−Mg drip line nuclei are also studied. 相似文献
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Self-consistent mean-field calculations of deformation energy surfaces have been performed for more than 30 exotic isotopes of the Kr, Sr, Zr and Mo elements. Our calculations extend to the proton drip line. We investigate the triaxial stability of the deformed ground states in the deformation regions N ≈ 38 and N ≈ 60. The results are in good agreement with the observed trends. 相似文献
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T. Rzaca-Urban W. Urban A. Kaczor J.L. Durell M.J. Leddy M.A. Jones W.R. Phillips A.G. Smith B.J. Varley I. Ahmad L.R. Morss M. Bentaleb E. Lubkiewicz N. Schulz 《The European Physical Journal A - Hadrons and Nuclei》2000,9(2):165-169
Neutron-rich, 88-94Kr nuclei, populated in spontaneous fission of 248Cm, have been studied with EUROGAM 2, by measuring prompt γ-rays. Many new excited states in even-even Kr isotopes have been
identified. For the first time spins and parities were determined experimentally in these nuclei. Our results indicate that
the quadrupole deformation of Kr isotopes will appear only above N = 58, as observed in Sr and Zr nuclei. The newly found 3- level at 1506.4 keV in 90Kr suggests the exsistence of a new region of increased octupole correlations, probably associated with the ν(d
5/2
h
11/2) pair of Δl = Δj = 3 orbitals.
Received: 18 September 2000 / Accepted: 18 October 2000 相似文献
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Quasi-band structures in 74Se, 78, 80Kr and 84Sr have been investigated using (p, 2nγ) reactions. The members of the quasi-γ band have been observed up to 5+ in 74Se, 78, 80Kr and up to 3+ in84Sr. The analyses of the energy systematics of the quasi-γ bands studied in this mass region as well as in other regions make clear the evolution of the quasi-γ band to the γ-band in well-deformed nuclei. In addition to these positive-parity bands, negative-parity levels were observed in 74Se, 80Kr and 84Sr. 相似文献
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Systematic Analysis of E(5) Critical-Point Nuclei in A~130 Region with Relativistic Mean Field Theory 下载免费PDF全文
The shape phase transition between spherical U(5) and γ-unstable O(6) nuclei is investigated systemically for the nuclei in the A~130 region by the constrained relativistic mean field theory. By examining potential energy surfaces and neutron Fermi energies, we suggest that 136Ba and 132,134Xe are possible nuclei with E(5) symmetry, which is favored by the observed ratio R4/2=(E+41-E+01)/(E+21-E+01). While the RMF predicted E(5) symmetry or 128,130,132Te cannot be supported by the observed ratio R4/2. Whether these nuclei are critical-point nuclei should further be examined in experiments. 相似文献
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F. Tondeur 《Nuclear Physics A》1981,359(2):278-288
The microscopic energy density method is applied to the study of nuclei with N ? 50 and Z = 32?40. The experimental Subshell effect at N = 56, which is not found in many previous works about this region, is well reproduced by the present self-consistent calculation. The existence of strongly deformed prolate isotopes of Zr and Sr for N ? 60 is also explained. A wide region of oblate shapes is predicted for N ? 60 and Z ? 36. The results also support the interpretation of low-energy isomers in the shape transition region as shape isomers. 相似文献
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Weak interaction rates are studied in neutron deficient Kr and Sr waiting-point isotopes in ranges of densities and temperatures relevant for the rp process. The nuclear structure is described within a microscopic model (deformed QRPA) that reproduces not only the half-lives but also the Gamow–Teller strength distributions recently measured. The various sensitivities of the decay rates to both density and temperature are discussed. Continuum electron capture is shown to contribute significantly to the weak rates at rp-process conditions. 相似文献
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O. V. Bespalova E. A. Romanovskii T. I. Spasskaya 《Bulletin of the Russian Academy of Sciences: Physics》2012,76(4):502-506
The neutron single-particle energies for Zr isotopes with neutron number N near 50, 70, and 82 are calculated using a mean field model with spherical dispersive optical potential. The calculated energy
values are in good agreement with experimental data and with predictions according to mass formula KTUY05. 相似文献
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The evolution of the ground-state nuclear shapes in neutron-rich Sr, Zr, and Mo isotopes, including both even-even and odd-A nuclei, is studied within a self-consistent mean-field approximation based on the D1S–Gogny interaction. Neutron separation energies and charge radii are calculated and compared with available data. A correlation between a shape transition and a discontinuity in those observables is found microscopically. While in Sr and Zr isotopes the steep behavior observed in the isotopic dependence of the charge radii is a consequence of a sharp prolate–oblate transition, the smooth behavior found in Mo isotopes has its origin in an emergent region of triaxiality. 相似文献