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In this article, we have reviewed our theoretical studies of collective rotations of high-K isomers in deformed nuclei. As one of methods which we have developed, the configuration-constrained total Routhian surface (CCTRS) based on a macroscopic–microscopic model has been found to be a powerful theoretical tool to describe isomers and their collective rotations. The CCTRS calculation provides a straightforward self-consistent way to determine the deformation which can change with increasing the collective rotational frequency and/or seniority of the state. To overcome the pairing collapse of numerical calculations encountered in the conventional pairing approach (e.g., BCS or Bogoliubov pairing) due to weakened pairings with unpaired nucleons in isomeric states, we have developed the CCTRS method using the particle-number-conserved (PNC) pairing approach in which the pairing is treated with the methodology of the many-body shell model. The CCTRS is calculated in a deformation lattice with the deformation parameters ( β 2 , γ , β 4 ). It is important that one should constrain the specific configuration in the CCTRS calculation, which has been achieved using the average Nilsson numbers to identify and track the single-particle orbitals specified in the intrinsic configuration of the isomer. With the CCTRS method, we have investigated many isomeric states and their rotational bands. As examples, we show in this review the calculations of collective rotational bands of isomers in rare-earth nuclei where rich data have been available. Furthermore, we have also developed a full microscopic configuration-constrained cranking model based on the Skyrme Hartree–Fock approach. Similar to the macroscopic–microscopic CCTRS, the pairing is treated by the PNC method to avoid the pairing collapse in pairing numerical calculations. As example, we show in this review the calculations of the rotational bands of 178 W isomers. [ABSTRACT FROM AUTHOR]

Based on our previous works about the configuration-constrained potential-energy-surface model investigating multi-quasiparticle high-K states, we have further developed the cranking configuration-constrained total Routhian surface method to calculate the collective rotations of the multiquasiparticle high-K states. The non-axial deformed Woods-Saxon potential has been adopted to obtain single-particle levels. The Woods-Saxon potential gives excellent single-particle level spacing, which is very important for the excitation energy calculations of high-K states. In order to improve pairing calculations, a particle-number-conserving pairing method has been incorporated into the TRS calculation. The calculated moments of inertia can well reproduce experimental values. The structures of the high-K states can be analyzed by the calculations. [ABSTRACT FROM AUTHOR]

Total-Routhian-surface calculations have been performed to investigate the shape evolutions of A~80 nuclei: 80-84Zr, 76-80Sr, and 84,86Mo. Shape coexistences of spherical, prolate, and oblate deformations have been found in these nuclei. Particularly for the nuclei 80Sr and 82Zr, the energy differences between two shape-coexisting states are less than 220 keV. At high spins, the g9/2 shell plays an important role in shape evolutions. It has been found that the alignment of the g9/2 quasiparticles drives nuclei to be triaxial. [ABSTRACT FROM AUTHOR]

Motivated by new experimental spectra in transfermium mass region, we have investigated broken-pair high-K multiparticle excited states and their rotational bands for the N = 150 isotones around Z = 100, by using the configuration-constrained pairing-deformation-frequency self-consistent total-Routhian-surface (TRS) model. In order to avoid the spurious phase transition encountered in the Bardeen-Copper-Schrieffer (BCS) pairing, the particle-number-conserving method has been employed for pairing calculations. Pairing correlations are remarkably reduced for the rotations of broken-pair multiparticle states. The present configuration-constrained TRS calculations reproduce reasonably existing experimental data. The abnormal feature in the recently observed Kπ = 8- bands of 252No and 250Fm would be associated with configuration mixing. [ABSTRACT FROM AUTHOR]

The total-Routhian-surface (TRS) calculation provides a powerful theoretical tool to describe the collective rotations of nuclei. It gives a straightforward way to determine nuclear deformation which can change with increasing rotational frequency. In most cases, however, TRS calculations with a conventional pairing approach (e.g., Bardeen-Cooper-Schrieffer pairing) encounter a nonconvergence problem when applied to sidebands which are built on broken-pair excited intrinsic configurations. To overcome this problem, we have developed the TRS calculations with a particle-number-conserving pairing method in which the pairing correlation is treated with the merit of the shell model. In this paper, we present the first results of the calculations, focusing on the sidebands of the 178W nucleus, investigating deformation changes and incurred effects on the rotational behaviors of sidebands. [ABSTRACT FROM AUTHOR]

Using the pairing-deformation-frequency self-consistent total-Routhian-surface and configuration-constrained potential-energy-surface calculations, we have studied nuclear deformation and its effect on the structure of nuclei. It was found that the high-order multipolarity-six (β6) deformation plays a significant role in superheavy nuclei. Possible non-collective high-spin isomeric states which locate in the second well of actinide nuclei have been investigated with the predictions of excitation energies and configurations. High-spin isomers can extend shape coexistence in A ~190 neutrondeficient nuclei. Triaxiality with γ~30° is found in the ground and excited rotational states of the A ~ 70 germanium isotopes. Octupole correlations have also been discussed in different mass regions. In recent experiments, the textbook nucleus 158Er has been reached at ultrahigh spins around 65ħ . We have studied 158Er ultrahigh-spin states by means of the self-consistent tilted-axis-cranking method based on the Nilsson shell correction and the Skyrme-Hartree-Fock model. The calculation with a γ ≈ 12° triaxial-strongly-deformed (TSD) excited configuration can well reproduce the observed large transitional quadrupole moment. It is demonstrated that the TSD minimum at negative γ deformation which appears in the principal-axis-cranking approach is a saddle point if allowing the rotational axis to change direction. [ABSTRACT FROM AUTHOR]

Total Routhian surface calculations have been performed to investigate rapidly rotating transfermium nuclei, the heaviest nuclei accessible by detailed spectroscopy experiments. The observed fast alignment in 252No and slow alignment in 254No are well reproduced by the calculations incorporating high-order deformations. The different rotational behaviors of 252No and 254No can be understood for the first time in terms of β6 deformation that decreases the energies of the vj15/2 intruder orbitals below the N = 152 gap. Our investigations reveal the importance of high-order deformation in describing not only the multiquasiparticle states but also the rotational spectra, both providing probes of the single-particle structure concerning the expected doubly magic superheavy nuclei. [ABSTRACT FROM AUTHOR]

The article presents a study which investigated the different rotational behaviors of 252No and 254No., which are said to be transfermium nuclei. In the study, the total Routhian surface (TRS) calculations were used to examine the substantial moments of inertia (MOI) difference between the two nuclei. The TRS method used is a pairing-deformation-frequency self-consistent calculation based on the cranked shell model.

Configuration-constrained potential-energy-surface calculations have been performed to investigate multiquasiparticle high-if states built on superdeformed minima in 192,194,196Pb and 198Po. The calculations predict that 196Pb and 198Po would be favorable candidates for the observation of low-lying superdeformed two- and four-quasiparticle high-K states. The possible decay paths and lifetimes that could lead to isomers are evaluated in detail for 196Pb. Comparisons between the predictions and previous observations of octupole-vibrational excitations indicate also that bands built on superdeformed high-K intrinsic states may compete with the octupole-vibrational mode in this mass region. The quadrupole moments of both the collective and intrinsic excitations are analyzed. [ABSTRACT FROM AUTHOR]

The partial conservation of the seniority symmetry in j = 9/2 shells has been discussed recently. In this work we show that the occurrence of the partial conservation of the seniority is the consequence of special properties of certain one-particle coefficients of fractional parentage. Further studies have also been done to pursue the similar special relations of the coefficients of fractional parentage in other single-;' shells with j ≲15/2. [ABSTRACT FROM AUTHOR]

We investigate the influence of deformation on the possible occurrence of long-lived K isomers in Hf isotopes around N = 116, using configuration-constrained calculations of potential-energy surfaces. Despite having reduced shape elongation, the multiquasiparticle states in 186,188Hf remain moderately robust against triaxial distortion, supporting the long expected occurrence of exceptionally long-lived isomers. The calculations are compared with available experimental data. [ABSTRACT FROM AUTHOR]

Using, for the first time, configuration-constrained potential-energy-surface calculations with the inclusion of β6 deformation, we find remarkable effects of the high-order deformation on the high-K isomers in 254No, the focus of recent spectroscopy experiments on superheavy nuclei. For shapes with multipolarity six, the isomers are more tightly bound and, microscopically, have enhanced deformed shell gaps at N=152 and Z=100. The inclusion of β6 deformation significantly improves the description of the very heavy high-K isomers. [ABSTRACT FROM AUTHOR]

We have calculated the strength functions of the Gamow-Teller transition processes from mirror pairs 46Ti–46Cr and 50Cr–50Fe to the odd-odd N = Z nuclei 46V and 50Mn. The calculations are carried out in fp model space with shell model diagonalization method. Calculations are compared with experimental observations. We have also discussed the effects of isospin symmetry breaking on the analogous transitions. [ABSTRACT FROM AUTHOR]

The article investigates the pharmacokinetics of injectable long-acting ivermectin (IVM) aqueous suspension in sheep following subcutaneous administration. Findings reveal that the IVM and hydrogenated castor oil solid-dispersion aqueous suspension has significant potential to be developed into an injectable sustained-release formulation, which could be administered as an edectocide through subcutaneous administration to sheep.

Isomeric states were observed in nuclei produced in an experiment at the RIKEN Nishina Center Radioactive Isotope Beam Factory following the in-flight fission of a 345 MeV/nucleon 238 U beam. Isomers reported in nuclei spanning a predicted prolate-oblate shape change boundary, 111 Zr ( E = 283.1 keV; τ = 0.326 (63) μ s), 112 Nb ( E = 44.2 keV; τ = 0.094 (26) μ s), 113 Nb ( E = 135.4 keV; τ = 0.846 (80) μ s), and 115 Mo ( E = 198.6 keV; τ = 63 (4) μ s), are compared to potential-energy surface calculations which gave a selection of low-lying configurations for each nucleus. Tentative assignments of ground and excited states were made based on energy similarities to the calculations, reduced transition probabilities of the decays, and constraints of transition multipolarities from γ -ray coincidence measurements. These assignments are suggestive of significant deformation being persistent for N > 70 in this region. In addition, isomers in 108 Nb, 109 Nb, 113 Tc, 117 Ru, 119 Ru, 120 Rh, and 122 Rh, not spanning the prolate-oblate transition discussed, are presented. [ABSTRACT FROM AUTHOR]

One can adopt two-step G-matrix approximations for the Brueckner-Hartree-Fock (BHF) calculations. The first G matrix is to soften the bare force, and the second one is to include the high-order correlations of the interaction in medium. The first G-matrix calculation for two-nucleon interaction should be done in the center-of-mass coordinate. As another alternative BHF approach, we have adopted the Vlow-k technique to soften the interaction and used the G matrix to include high-order correlations. The Vlow-k renormalization leads to high-momentum and low-momentum components of the interaction decoupled. With the Vlow-k potential, we have performed the BHF calculations for finite nuclei. The G-matrix elements with exact Pauli exclusions are calculated in the self-consistent BHF basis. To see effects from further possible correlations beyond BHF, we have simultaneously performed renormalized BHF (RBHF) calculations with the same potential. In RBHF, the mean field derived from realistic forces is modified by introducing the particle-occupation depletion resulting from many-body correlations. The ground-state energies and radii of the closed-shell nuclei, 4He, 16O, and 40Ca, have been investigated. The convergences of the BHF and RBHF calculations have been discussed and compared with other ab initio calculations with the same potential. [ABSTRACT FROM AUTHOR]

Starting from realistic nuclear forces, the chiral N³LO and JISP16, we have applied many-body perturbation theory (MBPT) to the structure of closed-shell nuclei, 4He and 16O. The two-body N³LO interaction is softened by a similarity renormalization group transformation while JISP16 is adopted without renormalization. The MBPT calculations are performed within the Hartree-Fock (HF) bases. The angular momentum coupled scheme is used, which can reduce the computational task. Corrections up to the third order in energy and up to the second order in radius are evaluated. Higher-order corrections in the HF basis are small relative to the leading-order perturbative result. Using the antisymmetrized Goldstone diagram expansions of the wave function, we directly correct the one-body density for the calculation of the radius, rather than calculate corrections to the occupation probabilities of single-particle orbits as found in other treatments. We compare our results with other methods where available and find good agreement. This supports the conclusion that our methods produce reasonably converged results with these interactions. We also compare our results with experimental data. [ABSTRACT FROM AUTHOR]

High-K isomeric states and their decays give access to the excited-state structure of neutron-rich rare-earth nuclides, where a maximum in β6 deformation has been predicted. Using extensions of the Nilsson-Strutinsky approach, including configuration constraints, we have calculated single-particle energies, and two-quasiparticle excitation energies. Their sensitivity to β6 deformation is discussed, as well as the possible influence of β6 deformation on collective rotational energies. [ABSTRACT FROM AUTHOR]

We have studied nuclear odd-even mass staggering with the Skyrme-Hartree-Fock-Bogoliubov theory by employing isoscalar and isovector contact pairing interactions. By reproducing the empirical odd-even mass differences of the Sn isotopie chain, the strengths of pairing interactions are determined. The optimal strengths adjusted in this work can give better description of odd-even mass differences than that fitted by reproducing the experimental neutron pairing gap of 120Sn. [ABSTRACT FROM AUTHOR]

The rotational symmetry is broken in mean-field models. The symmetry breaking may lead to significant effects even on the ground states of nuclei. The recent observations of enhanced collectivities in neutron-rich Fe and Cr isotopes are challenging the current calculations of mean-field models. By performing angular-momentum projection on mean-field potential energy surface (PES), we can obtain an angular-momentum-conserved PES at each given spin. With the projected PES, we have investigated the collectivity of neutron-rich Fe and Cr isotopes. The calculations reproduce well the excitation energies and electric quadrupole transitions of the collective excited states of the isotopes, indicating the importance of the restoration of the rotational symmetry. [ABSTRACT FROM AUTHOR]

Configuration-constrained potential-energy-surface calculations are performed including ß6 deformation to investigate high-K" isomeric states in nuclei around 254No and 270Ds, the heaviest nuclei where there have been some observations of two-quasiparticle isomers, while data for four-quasiparticle isomers are scarce. We predict the prevalent occurrence of four-quasiparticle isomeric states in these nuclei, together with their favored configurations. The most notable examples, among others, are Kπ = 20+ states in 266-268DS and 268,270Cn having very high K value, relatively low excitation energy, and well-deformed axially symmetric shape. The predicted isomeric states, with hindered spontaneous fission and a decay, could play a significant role in the future study of superheavy nuclei. [ABSTRACT FROM AUTHOR]

Collective rotational bands were observed for the first time in neutron-rich odd–odd 1 4 2 La by means of γ - γ - γ and γ - γ - γ - γ coincidence measurements of prompt fission γ rays from 2 5 2 Cf using multi-detector array Gammasphere. Similarity between the yrast band of 1 4 2 La and those of neighboring 1 4 4 La, 1 4 4 Ce was found and interpreted as quasiparticle excitations. PES calculations suggested triaxial deformation for the ground state of 142La. Considerable triaxial and near zero octupole deformations were deduced for the yrast band of 1 4 2 La by the TRS model calculations. The band-crossing observed in the yrast band of 1 4 2 La was interpreted to be caused by alignment of the (h 1 1 / 2 )2 proton pair, and the crossing frequency was best reproduced by the TRS calculations taking into account triaxial deformations. In contrast to the interpretations for the band crossing of 1 4 2 La, alignments of the (i 1 3 / 2 )2 neutron pair were found to be responsible for the band-crossing of the yrast band in the neighboring even-N 1 4 3 La, and triaxial degree of freedom was found to play a more significant role than octupole deformations in the nucleus, although its β 3 values deduced are large. [ABSTRACT FROM AUTHOR]

Aims: Diseases caused by pathogenic fungi was a major constrain in increasing productivity and improving quality of Panax notoginseng. The aim of this research was to evaluate the inhibitory activity of essential oils (EOs) from Asteraceae family, Chrysanthemum indicum and Laggera pterodonta, against pathogenic fungi of P. notoginseng. Methods and Results: The antifungal activity was investigated using multiple methods, disclosing that the EOs from C. indicum and L. pterodonta are active against hypha growth of different fungi but with different degrees of potency. Checkerboard testing indicated that the combination of EOs with hymexazol had synergistic effect against Pythium aphanidermatum, and exhibited additive effects against bulk of targeted pathogenic fungi. Besides, we found that the baseline sensitivity of Fusarium oxysporum to L. pterodonta EOs was higher than those of C. indicum by means of mycelium growth rate method. Finally, the practicability of those EOs as plant pesticide was confirmed by in vivo model showing that EOs can significantly inhibit the occurrence of root rot of P. notoginseng caused by F. oxysporum. Conclusion: Those studies suggest that the EOs from C. indicum and L. pterodonta had the potential to develop into new pollution‐free pesticides for the protection of precious Chinese herbal medicines. Significance and Impact of the Study: This study provided a new way of biological control for overcoming the frequent diseases occurrence of P. notoginseng. [ABSTRACT FROM AUTHOR]

We study weakly bound deformed nuclei based on the coordinate-space Skyrme Hartree-Fock-Bogoliubov (HFB) approach, in which a large box is employed for treating the continuum and large spatial extensions. When the limit of the core-halo deformation decoupling is approached, calculations found an exotic "egg"-like structure consisting of a spherical core plus a prolate halo in 38Ne, in which the near-threshold nonresonant continuum plays an essential role. Generally the halo probability and the decoupling effect in heavy nuclei can be hindered by high level densities around Fermi surfaces. However, deformed halos in medium-mass nuclei are possible as the negative-parity levels are sparse, e.g., in 110Ge. The deformation decoupling has also been demonstrated in pairing density distributions. [ABSTRACT FROM AUTHOR]

Using a new local cluster potential, cluster structures around double shell closures have been investigated. The calculations of spectra including electromagnetic transitions are in reasonable agreement with experimental data. Besides the nuclei, 20Ne, 44Ti, 60Zn, and 212Po, which have been intensively analyzed by cluster models, we have also studied two other good candidates, 52Ti and 136Te, for α-cluster structure in neutron-rich regions. In 136Te, the unexpectedly small B(E2;0+ 2+) would be due to the cluster characteristic. The new cluster potential without any readjustment of the parameter values has been also applied to the investigations of possible 6He-cluster structure in nuclei, 22Ne, 46Ti, 54Ti, 62Zn, and 138Te, which have the same doubly magic cores as the α-cluster nuclei above. Similarly good results can be obtained, compared with experimental data. It is an advantage that the new cluster potential suits the different types of cluster structures with a set of fixed parameters which do not need any readjustment for different cluster-core structures. [ABSTRACT FROM AUTHOR]

Energy-dependent phenomenological optical model potentials based on a single-folding model approach for the α-12C and deuteron-12C systems were obtained for incident energies between 10 and 100 MeV/nucleon. The Lane-consistent Bruy`eres Jeukenne-Lejeune-Mahaux model nucleon- nucleus potentials were used in these calculations. With only three free parameters, these potentials account satisfactorily for both angular distributions of elastic scattering cross sections and total reaction cross sections of both projectile-target systems within the energy range studied. Comparisons were made between the present potentials and other systematic phenomenological potentials. [ABSTRACT FROM AUTHOR]

Total-Routhian-surface calculations by means of the pairing-deformation-frequency self-consistent cranked shell model have been carried out for even-even germanium and selenium isotopes to search for possible stable triaxial deformations of nuclear states. The maximum triaxiality of |γ| = 30° is found in the ground and excited rotational states of the nuclei 64,74Ge. The calculations are compared with available experimental data, giving a general agreement with observed triaxiality in the isotopes. [ABSTRACT FROM AUTHOR]

A single-folding (SF) model analysis has been performed for α and deuteron elastic scattering from 58Ni, 90Zr, 116Sn, and 208Pb at incident energies between 10 and 100 MeV/nucleon with the Lane-consistent Bruyères Jeukenne-Lejeune-Mahaux model nucleon-nucleus potential. The energy dependence of a set of only three potential parameters was derived, and the resulting global optical model potentials were found to account well for α and deuteron elastic scattering within their studied energy ranges. The energy dependence of a real potential form factor is found to be important for describing α-nucleus scattering within large energy ranges. Corrections due to the compositeness of projectiles to the SF potentials were studied and were compared with theoretical estimations through the renormalization factor. Systematic differences in renormalization factors between α particles and deuterons were observed. [ABSTRACT FROM AUTHOR]

To investigate the prevalence and control of ectoparasites in China, 1200 questionnaires were delivered to caged commercial layer or parent hen keepers. Of the 860 respondents, 785 (91.3 per cent) claimed they found suspected ectoparasites in their birds and 833 samples were received. Ectoparasites of the species , or were found in 736 (88.4 per cent) samples. For caged commercial layers, was the most common ectoparasite (64.1 per cent). For caged parent hens, was the most common ectoparasite (46.9 per cent). Most bird keepers (95.0 per cent of commercial layer keepers and 74.9 per cent of parent hen keepers) used pyrethroids, organophosphates or other insecticides or acaricides to control ectoparasites. However, 34.6 per cent of layer keepers and 25.7 per cent of parent hen keepers did not re-treat their birds with insecticides or acaricides within two weeks after the first treatment. Sanitation procedures, including cleaning, washing and disinfection, were conducted in empty houses between flocks and on most commercial layer farms and parent hen farms. However, insecticides or acaricides were used in empty houses between flocks only in 24.8 per cent of commercial layer farms and in 36.1 per cent of parent hen farms. [ABSTRACT FROM PUBLISHER]

High-spin states in 169Re were studied and resulted in the identification of a strongly coupled band based on the 9/2- [514] Nilsson state and a decoupled band built on the h9/2 1/2- [541] intruder proton orbit. The cranked-shell-model calculations present configuration-dependent deformations that can explain the different band crossing frequencies. The 9/2- [514] band in 169Re shows the largest signature splitting at low spin among the known odd-mass Re isotopes. After the alignment of a pair of i13/2 neutrons, the phase of the splitting is inverted with a significantly reduced amplitude. For the 9/2- [514] bands in light odd-A Re isotopes, the signature splitting of the Routhians and its relation with the signature dependence of M1 transition matrix elements are investigated in connection with the deviation of nuclear shape from axial symmetry, suggesting an appreciable negative γ deformation for the very neutron-deficient odd-A Re isotopes. Additionally, a three-quasipariticle band was observed and assigned to be built likely on the &pie;9/2-[514] ® AE configuration. [ABSTRACT FROM AUTHOR]

Recent high-resolution experiments at JLab give the energy spectra of the hypernuclei , , and. However, their spins and parities of the excited states have not been known experimentally. In the present paper, we make a systematical theoretical investigation for the p-shell hypernuclei, within the shell model based on the nucleon–nucleon (NN) and hyperon–nucleon interactions. The effective NN interaction takes the finite-range density-dependent Gogny force, and the hyperon–nucleon interaction takes an empirical ΛN interaction which includes the ΛN–ΣN and ΣN–ΣN coupling effects. The shell model with the Gogny force without parameters being refitted can reasonably describe both spectra and binding energies of the p-shell nuclei, which gives a confidence for the further calculations of hypernuclei. We compare our results with experimental data as well as various theoretical calculations, and explain the recent experimental hypernuclear spectra observed at JLab. [ABSTRACT FROM AUTHOR]

The neutron-rich zirconium isotopes are a key testing ground for nuclear models due to their sensitivity to shape changes, and because they cross the r-process path of explosive nucleosynthesis. Furthermore, recent experimental data have revealed a high-spin isomer in l08Zr. Here we report the results of configuration-constrained potential-energy-surface calculations of ground states and high-K states in 104-110Zr, restricted to quadrupole and hexadecapole shapes. These calculations enable the existing isomer data to be understood, and predictions are made for 110Zr. [ABSTRACT FROM AUTHOR]

We apply the Gamow shell model to study 25-31F isotopes. As both internucleon correlations and continuum coupling are properly treated therein, the structure shape of 31F at large distance can be analyzed precisely. For this, one-nucleon densities, root-mean-square radii, and correlation densities are calculated in neutron-rich fluorine isotopes. It is then suggested that 31F exhibits a two-neutron halo structure, built from both continuum coupling and nucleon-nucleon correlations. [ABSTRACT FROM AUTHOR]

The Gamow shell model is utilized to describe nuclear observables of the weakly bound and resonance isotonic states of 16O at the proton drip-line. It is hereby shown that the presence of continuum coupling leads to complex Coulomb contributions in the spectrum of these isotones. The necessity to include the effects of three-body forces, either by a direct calculation or by adding an A dependence to the nucleon-nucleon interaction, already noticed in other theoretical models, is pointed out. It is also demonstrated that our approach is predictive for reaction observables. [ABSTRACT FROM AUTHOR]

The very neutron-deficient nuclide 129Pm was produced via the 92Mo(40Ca, p2n) reaction and identified for the first time by using the X-γ coincidence in combination with a He jet tape transport system. According to the decay curve of a 99 keV γ-ray which corresponds to the known &frac52; → ½ transition in the daughter nucleus 129Nd of the 129Pm decay, the half-life of 129Pm was determined to be 2.4(9) s. Based on the nuclear potential energy surface (PES) calculations, the ground-state spin-parity of 129Pm was predicted as &frac52; which is favorable to feed a &frac52; low-lying state in the daughter nucleus 129Nd via the (EC 1β+) decay. [ABSTRACT FROM AUTHOR]

High-spin levels of Mo have been reinvestigated by analyzing the high statistics -- and --- coincidence data from the spontaneous fission of Cf taken with the Gammasphere detector array. Two bands and 30 new transitions have been identified. A potential energy surface calculation has been performed. The calculation confirmed the 3/2[411] configuration of the ground state band and 5/2[532] for the 346keV excited band, as assigned in the previous work. The two newly established bands were proposed to be one- and two-phonon vibrational bands coupling to the 5/2[532] Nilsson orbital, respectively. Triaxial projected shell model calculations have been applied to explain the level structure and are found in good agreement with experimental data. [ABSTRACT FROM AUTHOR]

We study nuclear multipole resonances in the framework of the random-phase approximation by using the chiral potential NNLOsat. This potential includes two- and three-body terms that have been simultaneously optimized to low-energy nucleon-nucleon scattering data and selected nuclear structure data. Our main focuses have been the isoscalar monopole, isovector dipole, and isoscalar quadrupole resonances of the closed-shell nuclei, 4He, 16,22,24O, and 40,48Ca. These resonance modes have been widely observed in experiment. In addition, we use a renormalized chiral potential Vlow-k, based on the N3LO two-body potential by Entem and Machleidt [Phys. Rev. C 68, 041001 (2011)]. This introduces a dependency on the cutoff parameter used in the normalization procedure as reported in previous works by other groups. While NNLOsat can reasonably reproduce observed multipole resonances, it is not possible to find a single cutoff parameter for the Vlow-k potential that simultaneously describes the different types of resonance modes. The sensitivity to the cutoff parameter can be explained by missing induced three-body forces in the calculations. Our results for neutron-rich 22,24O show a mixing nature of isoscalar and isovector resonances in the dipole channel at low energies. We predict that 22O and 24O have low-energy isoscalar quadrupole resonances at energies lower than 5 MeV. [ABSTRACT FROM AUTHOR]

Background: Nuclear collective rotations have been successfully described by the cranking Hartree-Fock- Bogoliubov (HFB) model. However, for rotational sidebands which are built on intrinsic excited configurations, it may not be easy to find converged cranking HFB solutions. The nonconservation of the particle number in the BCS pairing is another shortcoming. To improve the pairing treatment, a particle-number-conserving (PNC) pairing method was suggested. But the existing PNC calculations were performed within a phenomenological one-body potential (e.g., Nilsson or Woods-Saxon) in which one has to deal the double-counting problem. Purpose: The present work aims at an improved description of nuclear rotations, particularly for the rotations of excited configurations, i.e., sidebands. Methods: We developed a configuration-constrained cranking Skyrme Hartree-Fock (SHF) calculation with the pairing correlation treated by the PNC method. The PNC pairing takes the philosophy of the shell model which diagonalizes the Hamiltonian in a truncated model space. The cranked deformed SHF basis provides a small but efficient model space for the PNC diagonalization. Results: We have applied the present method to the calculations of collective rotations of hafnium isotopes for both ground-state bands and sidebands, reproducing well experimental observations. The first up-bendings observed in the yrast bands of the hafnium isotopes are reproduced, and the second up-bendings are predicted. Calculations for rotational bands built on broken-pair excited configurations agree well with experimental data. The band-mixing between two Kπ = 6+ bands observed in l76Hf and the K purity of the l78Hf rotational state built on the famous 31 yr Kπ = 16+ isomer are discussed. Conclusions: The developed configuration-constrained cranking calculation has been proved to be a powerful tool to describe both the yrast bands and sidebands of deformed nuclei. The analyses of rotational moments of inertia help to understand the structures of nuclei, including rotational alignments, configurations, and competitions between collective and single-particle excitations. [ABSTRACT FROM AUTHOR]

The spectroscopy of 73Ge has been investigated via the 70Zn(7Li,3np) 73Ge fusion-evaporation reaction. A previously known band built on the v(f5/2) orbital is extended up to higher-spin states and a new rotational band built on the v(g9/2) orbital is established. The observed band crossing and shape evolution induced by the alignment in 73Ge are studied in comparison with the similar structures in the neighboring N = 41 isotones and the cranked Woods-Saxon-Strutinsky calculations by means of total-Routhian-surface (TRS) methods. The inversion of the order of the g9/2 neutron and the g9/2 proton crossing frequency observed in the negative-parity v(f5/2) bands between 73Ge and 75Se, 77Kr can be ascribed to their different triaxial deformations. At higher spins, both the v(f5/2) and v(g9/2) bands in 73Ge undergo a shape evolution with sizable alignments occurring. The characters of large signature splitting in v(g9/2) band of 73Ge are discussed. [ABSTRACT FROM AUTHOR]

Background: The previously reported levels assigned to 151,152,153pr have recently been called into question regarding their mass assignment. Purpose: We clarify the above questioned level assignments by measuring γ transitions tagged with A and Z in an in-beam experiment in addition to the measurements from 252Cf spontaneous fission (SF) and establish new spectroscopic information from N = 84 to N = 94 in the Pr isotopic chain. Methods: The isotopic chain 143-153pr has been studied from the spontaneous fission of 252Cf by using Gammasphere and also from the measurement of the prompt y rays in coincidence with isotopically identified fission fragments using VAMOS++ and EXOGAM at Grand Accelerateur National d'Ions Lourds (GANIL). The latter were produced using 238U beams on a 9Be target at energies around the Coulomb barrier. The γ-γ-γ-γ data from 252Cf (SF) and those from the GANIL in-beam A- and Z-gated spectra were combined to unambiguously assign the various transitions and levels in 151,152,153Pr and other isotopes. Results: A band of 3 new transitions added to the known level in 145Pr, 9 new transitions in two new bands in 147Pr, 6 new transitions in a new level scheme for 148Pr, two new bands with 17 new transitions in 149Pr, and two new bands with 11 new transitions in 150Pr were identified by using γ-γ-γ and γ-γ-γ-γ coincidences and A and Z-gated γ-γ spectra. The transitions and levels previously assigned to 151,153Pr have been confirmed by the (A,Z)-gated spectra. Small changes have been made to their original level schemes. The transitions previously assigned to 152Pr are now assigned to 151Pr on the basis of the (A,Z)-gated spectra. Two new bands with 20 new transitions in 152Pr and one new band with 7 new transitions in 153Pr are identified from the γ-γ-γ-γ coincidence spectra and the (A,Z)-gated spectrum. In addition, new γ rays are also reported in 143,146Pr. Conclusions: New levels of 145,147-153pr have been established, reliable mass assignments of the levels in 151,152,153pr have been given in the present work, and new transitions have been identified in 143-146Pr showing the new avenues that are opened by combining the two experimental approaches. [ABSTRACT FROM AUTHOR]

For a shape-soft nucleus, the deformation change with increasing angular momentum of rotation can be significant. Total-Routhian-surface (TRS) calculations include the shape changes, but angular momentum is not conserved (neither is it a good quantum number, nor is it kept unchanged in the whole TRS mesh). In the projected shell model (PSM), the angular momentum appears as a good quantum number, but calculations have usually been performed with fixed deformation. In the present work, by performing angular-momentum projection on the mean-field potential-energy surface (PES), we can obtain an angular-momentum-conserved PES which gives deformation for a rotational state at a given spin. In order to investigate the shape-changing effect, we have chosen neutron-deficient Hg and Pb isotopes in which shape coexistence occurs. We interpret the irregular rotational behavior of the oblate bands at low spin as arising from deformation changes which are induced by collective rotation. At higher spin, the oblate rotational spectrum can also be influenced by the crossing between the K = 0 ground-state band and a low-AT two-quasineutron band. Calculated g factors for the states of oblate bands are given for future experimental testing, and the intrinsic structures of high-A" oblate states are investigated. [ABSTRACT FROM AUTHOR]

An inelastic excitation experiment was performed with a 12Be beam at 29 MeV/u on a carbon target. New resonances close to the respective cluster separation thresholds were observed in 12Be for the 4He + 8He and 6He + 6He decay channels, confirming the previously proposed molecular rotational bands. Using the model-independent angular correlation analysis, a 0+ spin parity is assigned to the remarkably large peak at 10.3 MeV in the 4He + 8He channel. A distorted wave Born approximation (DWBA) calculation was compared to the experimental differential cross section of this state, resulting in a largely enhanced monopole transition matrix element of 7.0 ± 1.0fm², in good agreement with the generalized two-center cluster model (GTCM) prediction assuming a preformed α-4n-α configuration. Together with the previously reported large cluster spectroscopic factor, the strong clustering in 12Be is well demonstrated. The detection focused on the most forward angles, by using a zero-deg telescope, is essential in the present measurement. [ABSTRACT FROM AUTHOR]

Excited states in the N = 102 isotones 166Gd and 164Sm have been observed following isomeric decay for the first time at RIBF, RIKEN. The half-lives of the isomeric states have been measured to be 950(60) and 600(140) ns for 166Gd and 164Sm, respectively. Based on the decay patterns and potential energy surface calculations, including β6 deformation, a spin and parity of 6- has been assigned to the isomeric states in both nuclei. Collective observables are discussed in light of the systematics of the region, giving insight into nuclear shape evolution. The decrease in the ground-band energies of 166Gd and 164Sm (N = 102) compared to 164Gd and 162Sm (N = 100), respectively, presents evidence for the predicted deformed shell closure at N = 100. [ABSTRACT FROM AUTHOR]

The Gamow-Teller (GT) strength distributions and isobaric analog resonance (IAR) states of several N = Z + 2 nuclei with mass number A = 42 - 58 are studied by using a self-consistent Skyrme Hartree-Fock-Bogoliubov method plus quasiparticle random phase approximation (HFB+QRPA) formalism. The isoscalar spin-triplet pairing interaction is included in QRPA on top of the isovector spin-singlet one in the HFB method. It is found that the isoscalar pairing correlations mix largely the (νj> → πj<) configurations into the low-energy states, and this mixing plays an important role in the formation and in the collectivity of these low-energy states. Furthermore, the observed excitation energy of the low-energy GT state with respect to the IAR can be well reproduced when the strength of isoscalar pairing is about 1.0-1.05 times that of the isovector pairing, irrespective of the adopted Skyrme interactions. In N = Z + 2 nuclei in the middle of the pf-shell, a mutual cooperative effect of isoscalar pairing and tensor interaction is found; namely, the tensor force reduces the spin-orbit splittings and enhances the effect of the isoscalar pairing. [ABSTRACT FROM AUTHOR]