Mixed-symmetry octupole and hexadecapole excitations in the N=52 isotones

General formalism of collective motion for any deformed system

Based on Bohr model, we have presented a general formalism describing the collective motion for any deformed system, in which the collective Hamiltonian is expressed as vibrations in the body-fixed frame, rotation of whole system around the laboratory frame, and coupling between vibrations and rotation. Under the condition of decoupling approximation, we have derived the quantized Hamiltonian operator. Based on the operator, we have calculated the rotational spectra for some special octupole and hexadecapole deformed systems, and shown their dependencies on deformation. The result indicates th…

Nonaxial-octupole Y_{32} correlations in N = 150 isotones from multidimensional constrained covariant density functional theories

The non-axial reflection-asymmetric $β_{32}$ shape in some transfermium nuclei with N=150, namely $^{246}$Cm, $^{248}$Cf, $^{250}$Fm, and $^{252}$No are investigated with multidimensional constrained covariant density functional theories. By using the density-dependent point coupling covariant density functional theory with the parameter set DD-PC1 in the particle-hole channel, it is found that, for the ground states of $^{248}$Cf and $^{250}$Fm, the non-axial octupole deformation parameter $β_{32} > 0.03$ and the energy gain due to the $β_{32}$ distortion is larger than 300 keV. In $^{246}$Cm…

协变密度泛函理论中 N=184 同中子素的奇异非轴对称八极形状

Exotic nonaxial-octupole shapes in $N=184$ isotones from covariant density functional theories

本文用协变密度泛函理论揭示 N=184 同中子素 284Fm、286No、288Rf、290Sg 的基态具有非轴对称八极形变，能量增益约 1 MeV，并归因于质子轨道 1i13/2 和 2f7/2 的关联。

Multi-dimensional potential energy surfaces and non-axial octupole correlations in actinide and transfermium nuclei from relativistic mean field models

We have developed multi-dimensional constrained covariant density functional theories (MDC-CDFT) for finite nuclei in which the shape degrees of freedom β_{λμ} with even μ, e.g., β_{20}, β_{22}, β_{30}, β_{32}, β_{40}, etc., can be described simultaneously. The functional can be one of the following four forms: the meson exchange or point-coupling nucleon interactions combined with the non-linear or density-dependent couplings. For the pp channel, either the BCS approach or the Bogoliubov transformation is implemented. The MDC-CDFTs with the BCS approach for the pairing (in the following label…

The decay of quadrupole-octupole $1^-$ states in $^{40}$Ca and $^{140}$Ce

Background: Two-phonon excitations originating from the coupling of two collective one-phonon states are of great interest in nuclear structure physics. One possibility to generate low-lying $E1$ excitations is the coupling of quadrupole and octupole phonons. Purpose: In this work, the $γ$-decay behavior of candidates for the $(2_1^+\otimes 3_1^-)_{1^-}$ state in the doubly-magic nucleus $^{40}$Ca and in the heavier and semi-magic nucleus $^{140}$Ce is investigated. Methods: $(\vecγ,γ')$ experiments have been carried out at the High Intensity $γ$-ray Source (HI$γ$S) facility in combination wit…