Simultaneous description of four positive parity bands and four negative parity bands

Abstract

The extended coherent state model is further extended in order to describe two dipole bands of different parities. The formalism provides a consistent description of eight rotational bands. A unified description for spherical, transitional and deformed nuclei is possible. Projecting out the angular momentum and parity from a sole state, the K π = 1 + band acquires a magnetic character, while the electric properties prevail for the other band. Signatures for a static octupole deformation in some states of the dipole bands are pointed out. Some properties which distinguish between the dipole band states and states of the same parity but belonging to other bands are mentioned. Interesting features concerning the decay properties of the two bands are found. Numerical applications are made for 158 Gd, 172 Yb, 228,232 Th, 226 Ra, 238 U and 238 Pu, and the results are compared with the available data.

Non-yrast nuclear spectra in a model of coherent quadrupole-octupole motion

“…The condition (8) imposes certain correlations between the mass, stiffness and inertia parameters of the model Hamiltonian (3), corresponding to a coherent quadrupole-octupole motion of the system. Note that here the term "coherent" is used in the context of the mixing between the quadrupole and octupole degrees of freedom, which is different from the meaning of the same term used in [16]. In this case the Hamiltonian is obtained in a simple form…”

“…In principle, the systematic analysis of the non-yrast levels with alternating parity may favour different band-coupling schemes in the different nuclear regions allowing one to compare the capabilities of various theoretical models. For example, an extended study of non-yrast energy sequences with different parities has been implemented within the Extended Coherent States Model [16] by considering a coupling of the β and γ bands with respective bands possessing the same spins but opposite parities, as well as a coupling between K π = 1 + and K π = 1 − energy sequences. In the model scheme of the present work the positive-parity β-band appears connected to a negative-parity non-yrast sequence with odd angular momenta in the same way as in the yrast alternating-parity configuration.…”

Description of nuclear octupole and quadrupole deformation close to axial symmetry: Critical-point behavior ofRa224andThBizzeti1, Bizzeti‐Sona2 2008Phys. Rev. C401330View full textAdd to dashboardCite

“…The simultaneous investigation of axial and nonaxial modes, as has been performed via the extended coherent state model in Refs. [17][18][19][20], is outside our present possibilities.…”

“…[9,12]. Finally, an extension of the extended coherent state model [17] has been developed by Raduta and co-workers [18][19][20], which also includes the lowest K π = 1 + and 1 − bands in the model space, and the model predictions have been compared with the experimental data for several nuclei of the regions of the actinides and of the rare earths.…”

Parity Partner Bands in $^{163}$Lu: A novel approach for describing the negative parity states from a triaxial super-deformed band

“…These bands are thus parity partners, as defined in Refs. [24][25][26][27]. From the above arguments it results that within the angular momentum space the action of the parity operator to any angular momentum vector I leads to -I. Consequently, the parity operator commutes with the quantal Hamiltonian H and therefore the eigenfunctions of H are of either positive or negative parity.…”