Three different ways for description of binding energy of superheavy nuclei are discussed. First, one can consider superheavy nuclei as a part of a whole system of nuclei for which a global mass formula is found. Another way is the detailed local description of energy of superheavy nuclei taking into account the effects of shells and subshells. The third way of description, applied for nuclei in the region limited by principal magic numbers, is attached to the beta-stability line.
Potential energy surfaces and fission barriers of superheavy nuclei are analyzed in the macroscopic-microscopic model. The Lublin-Strasbourg Drop (LSD) is used to obtain the macroscopic part of the energy, whereas the shell and pairing energy corrections are evaluated using the Yukawa-folded potential. A standard flooding technique has been used to determine the barrier heights. It was shown the Fourier shape parametrization containing only three deformation parameters reproduces well the nuclear shapes of nuclei on their way to fission. In addition, the non-axial degree of freedom is taken in…
Potential energy surfaces of even-even superheavy nuclei are evaluated within the macroscopic-microscopic approximation. A very rapidly converging analytical Fourier-type shape parametrization is used to describe nuclear shapes throughout the periodic table, including those of fissioning nuclei. The Lublin Strasbourg Drop and another effective liquid-drop type mass formula are used to determine the macroscopic part of nuclear energy. The Yukawa-folded single-particle potential, the Strutinsky shell-correction method, and the BCS approximation for including pairing correlations are used to obta…
We study the effects of higher-order deformations $β_λ$ ($λ=4,6,8,$ and $10$) on the ground state properties of superheavy nuclei (SHN) near the doubly magic deformed nucleus $^{270}$Hs by using the multidimensionally-constrained (MDC) relativistic mean-field (RMF) model with five effective interactions PC-PK1, PK1, NL3$^{*}$, DD-ME2, and PKDD. The doubly magic properties of $^{270}$Hs are featured by the large energy gaps at $N=162$ and $Z=108$ in the single-particle spectra. By investigating the binding energies and single-particle levels of $^{270}$Hs in multidimensional deformation space, …
Atomic nuclei are composite systems, and they may be dynamically excited during nuclear reactions. Such excitations are not only relevant to inelastic scattering but they also affect other reaction processes such as elastic scattering and fusion. The coupled-channels approach is a framework which can describe these reaction processes in a unified manner. It expands the total wave function of the system in terms of the ground and excited states of the colliding nuclei, and solves the coupled Shrödinger equations to obtain the $S$-matrix, from which several cross sections can be constructed. Thi…
Alpha decay favoured isotopes of some superheavy nuclei: Spontaneous fission versus alpha decay
自发裂变和α衰变是超重核的主要衰变方式。与自发裂变半衰期相比,具有较小α衰变半衰期的超重核将在裂变中存活,并且可以通过α衰变在实验室中检测到。我们研究了Z = 100-130原子范围内的一些超重元素的α衰变半衰期和自发半衰期。超重核的自发裂变半衰期已经用唯象公式计算,α衰变半衰期用Viola-Seaborg-Sobiczewski公式(Sobiczewski et al. 1989)、Brown(1992)的半经验关系式和Dasgupta-Schubert and Reyes(2007)基于广义液滴模型的公式计算。结果报告于此。
Systematic Study of Survival Probability of Excited Superheavy Nuclei
用统计模型研究了含$100 \leq Z \leq 134$的超重核对中子发射和裂变的稳定性。特别是对这些SHN的1n沟道中抗裂变的生存概率进行了系统的研究。在目前的计算中,中子分离能和壳层修正能始终取自有限程液滴模型的计算结果,该模型预测了SHN在Z=115和N=179附近的稳定岛。事实证明,在最佳激发能下激发SHN的1n通道中计算的存活概率在Z=115和N=179附近最大化的意义上,这种稳定岛对于激发SHN持续存在。这表明1n沟道中的存活几率主要由核壳效应决定。
This work investigated the first-chance survival probabilities of highly excited compound superheavy nuclei in the prospect of synthesizing new superheavy elements. The main feature of our modelings is the adoption of microscopic temperature dependent fission barriers in calculations of fission rates. A simple derivation is demonstrated to elucidate the connection between Bohr-Wheeler statistical model and imaginary free energy method, obtaining a new formula for fission rates. The best modeling is chosen with respect to reproducing the experimental fission probability of $^{210}$Po. Systemati…
Octupole deformation in neutron-rich actinides and superheavy nuclei and the role of nodal structure of single-particle wavefunctions in extremely deformed structures of light nuclei
Superheavy Nuclei in the Quark-Meson-Coupling Model
本文介绍了用夸克-介子耦合模型(QMC)对96 < Z < 136和118 < N < 320范围内偶偶超重核基态性质进行综合计算的初步结果。本文报道了100 < Z < 136的偶偶核的基态结合能、四极形变与中子数和质子数的关系以及Q值$_α$,并与已有的实验数据和宏观-微观模型的预测进行了比较。预测的性质的核,包括Q $_α$值,规划未来的实验相关。
The competition between alpha- and beta+/EC-decay modes is studied systematically in nuclei along the alpha-decay chains following the synthesis of superheavy nuclei with Z = 119 and Z = 120. A microscopic approach based on deformed self-consistent Hartree-Fock mean-field calculations with Skyrme forces and pairing correlations is used to describe the beta+ and electron capture weak decays, whereas the alpha-decay is estimated from existing phenomenological expressions. It is shown that alpha-decay is in most cases the dominant decay mode, but interesting instances are identified where the hal…