Search

The validity of the extended Grodzins product rule (GPR) for higher spins in the ground bands of even [Formula: see text], even [Formula: see text] nuclei of the light mass region of Cd to Zn chain of isotopes is studied. The plots of [Formula: see text]2, [Formula: see text]) versus [1/[Formula: see text]] ([Formula: see text], 6[Formula: see text] provide test of the linear relationship of the two entities. There seems to be a good correlation of the two entities at these higher spin states for most of the nuclei studied here. The deviations from linearity in specific cases are found to be useful for studying the variations in the nuclear structures involved. From these linearity plots, the structural change at higher spin in some nuclei involving subshell gaps, as reflected in the anomalous rise or saturation, leads to further insight into the under lying microscopic structure.

The well known, one-parameter Davydov–Filippov model (DFM) or its variants have been used often to study the inter band [Formula: see text]-g B(E2) ratios for the triaxially deformed nuclei. Here, its application for the axially deformed nuclei with [Formula: see text] less than [Formula: see text] is illustrated, which has not received attention so far. Instead of the usual practice of studying the gamma-ground B(E2) ratios, we focus on the absolute B(E2) values in DFM. It offers a wholly new role of the [Formula: see text]-variable in explaining the spectral features of the axially deformed nuclei. Further, it illustrates the intimate relationship of the [Formula: see text] variable and the quadrupole deformation variable [Formula: see text]. Additionally, a unified view of the various differing patterns of the variation of the [Formula: see text]-g B(E2) ratios versus [Formula: see text] is presented.

In a previous study of the collective multiphonon bands in $^{154}\mathrm{Gd}$, using the microscopic dynamic pairing plus quadrupole model, data for eight $K$ bands were analyzed. In the last four decades, its decay scheme is significantly revised and the nuclear theory has undergone a significant change. Special focus is on new weak intensity transitions in several bands and on the reassigned levels in its decay scheme. The present study represents a detailed revised analysis of the collective even parity bands below 2.1 MeV. Also, a discussion is given on the nature of the ${K}^{\ensuremath{\pi}}={0}^{+}$ excited bands, validity of band mixing approach, and of the assumption of shape coexistence of \ensuremath{\beta} band with ground band. Comparison is made with the $X$(5) analytical symmetry and the algebraic interacting boson model predictions. Discussion of the $2n$ transfer reactions is given. The validity of the multiphonon view of the ${K}^{\ensuremath{\pi}}={4}^{+}$ and ${2}_{2}^{+}$ bands is also studied.

In the collective spectra of atomic nuclei, the level energy [Formula: see text] varies with atomic number [Formula: see text] and neutron number [Formula: see text]. Also the [Formula: see text]2 decay-reduced transition probability [Formula: see text] is related to the energy [Formula: see text]. The product [Formula: see text] is constant according to Grodzins product rule, independent of the vibration or rotational status of the nucleus. The product rule is often used for determining [Formula: see text] from the known [Formula: see text]. However, the variation of the product with various parameters is also suggested in the literature. Hence, a detailed global study of this rule for [Formula: see text] region is warranted. We use a novel method of displaying the linear relation of [Formula: see text] with [Formula: see text] for the isotopes of each element (Xe–Pt), instead of their variation with [Formula: see text] or [Formula: see text]. Through our work, we firmly establish the global validity of the Grodzins relation of [Formula: see text], being proportional to the moment of inertia, except for the deviation in specific cases. Our [Formula: see text] versus [Formula: see text] plots provide a transparent view of the variation of the low-energy nuclear structure. This gives a new perspective of their nuclear structure. Also the various theoretical interpretations of [Formula: see text]s and the energy [Formula: see text] are reviewed.

The recently extended level structure of 104–108Mo isotopes, with g-, γ- and the possible Kπ = 4+ 2γ phonon band structures have been studied in the interacting boson model-1. The unique features of these Mo isotopes with large quadrupole deformation β2, and the γ-soft vibrational band structures as reflected in the γ–g B(E2) ratios have been reproduced. The evidence for the 2γ-phonon bands in 104,106Mo is discussed.

The level structure of 144-150Nd is analysed taking into account the experimental information available, with respect to the symmetries of IBM-1. The level energies, B(E2) values, and interband B(E2) ratios are compared with available data. The adopted level schemes of 144-150Nd and the varying limitations of the interacting boson model in these isotopes are discussed.

A comparison of the efficacy of the SU(5) and O(6) limits of the interacting boson model in reproducing the spectra of the neutron deficient 136-140Sm isotopes is presented. The role of the ( beta , gamma ) deformation inducing nu 0 and nu 2 terms in the IBM-1 Hamiltonian for generating the proper level spacings of the odd-even spins in the Kpi =2+ band and up to high spins Ipi

The proton neutron interacting boson model (IBM-2) has been used to make a systematic study of Strontium isotopes in this mass region of A ~ 80 with 38 N 48 and Z = 38. The three-term Talmi–Otsuka general Hamiltonian in the framework of the neutron proton version of the Interaction boson model was used to perform the calculations. The yrast levels energy are reproduced. The beta and gamma band energy levels also matched well. The reduced transition probabilities were also calculated and were found to be in agreement with the experimental values. In addition, g-factor for the state was evaluated. Possible candidates for mixed symmetry states were also predicted for several nuclei in this isotopic chain.

The experimental data of interband γ-g B(E2) ratios for even-even light Te-Sm nuclei (66 ≤ N ≤ 78) is compared with the predictions of the rigid triaxial model to search for a correlation between the nuclear structure variation with the asymmetry parameter γ0 of the model.

The size of the proton subshell gap between the ${\mathit{d}}_{5/2}$ and ${\mathit{h}}_{11/2}$ orbitals is reviewed. The need of revising the microscopic calculations with increased energy gap is reexamined for N\ensuremath{\ge}82 nuclei. Both for occupation probabilities and the nuclear structure of N=82 isotones and the $^{146\mathrm{\ensuremath{-}}154}\mathrm{Sm}$ isotopes, the increased gap at Z=64 is not inconsistent with experiment, except that increased quadrupole strength is required for obtaining the same structure. The use of alternative values of boson numbers in the interacting boson model (IBM) for N88 nuclei is investigated. In a phenomenological IBM calculation there is no a priori need of the use of subshell closure. In the empirical studies for this region the use of the Z=64 subshell does lead to elegant systematics in some cases but it also leads to inconsistencies in other cases. Dependence of collective deformation effect on the slope of particular orbitals, rather than on gap size only, is illustrated.

Dynamic deformation theory based on the pairing plus-quadrupole model is employed for a detailed study of the N=88 transitional nucleus 152Gd. Comparisons with experiment and with other models are presented for the potential minimum and related properties, B(E2) values, rho (E0), X(EO/E2) and delta (E2/M1) values for transitions from seven 2+ states and a number of other states below 2 MeV. Brief comparisons with two N=88 isotones (148Nd and 150Sm) and with five Z=64 isotopes (150,154,156,158,160Gd) are also given.

The weak transitions in the decay of125Sb have been investigated through gamma ray measurements with high resolution X-ray and with large volume Ge(Li) detectors. The 172.6, 178.8 and 198.5 keV gamma rays are confirmed, while others previously reported were not. Accurate intensities were obtained for the stronger transitions. The weighted averages of these intensities which cover the range of 116 to 670 keV are useful for calibration of Ge(Li) systems.

Interband B(E2) values from dynamic deformation theory using the P+QxQ interaction reproduce recent accurate data from Doppler shift recoil experiment contrary to recent claims.