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We studied the ground state band properties of 212 Po, 218 Rn and 232 U using the binary cluster model. The nuclei are treated as a 208 Pb-core plus a cluster interacting via a local potential of Saxon–Woods type functional form whose parameters are derived from Michigan-3-Yukawa (M3Y) microscopic potential model. Further correction in the internal structure of the hybrid potential model is attributed to the nucleon distribution in the overlap region of the core-cluster system. Overall our calculated results are found to compare favourably well with available experimental data. [ABSTRACT FROM AUTHOR]

The microscopic cluster model approach has been performed to study the nuclear structure of the lightest and heaviest two-neutron halo nuclei, 6He and 22C, respectively. The matter radius and binding energy for the 6He and 22C nuclei are calculated and the effect of the core deformation (20C) on the properties of 22C nuclei is also discussed. Calculations have shown that the microscopic cluster model provides a good description of binding energy as well as matter radius in comparison to experimental data. The fittings of some parameters such as central potential depth (Vo), empirical constant (ro), and surface diffuseness value (a) are discussed to find agreement in the results with the available experimental data. The exotic properties of two-neutron halo nuclides 6He and 22C such as weak binding energy, abnormal large matter radius, and Borromean system have been confirmed in the present work. [ABSTRACT FROM AUTHOR]

We discuss an algebraic treatment of four-body clusters which includes both continuous and discrete symmetries. In particular, tetrahedral configurations with T d symmetry are analyzed with respect to the energy spectrum, transition form factors and B ( E L ) values. It is concluded that the low-lying spectrum of 16 O can be described by four α particles at the vertices of a regular tetrahedron, not as a rigid structure but rather a more floppy structure with relatively large rotation–vibration interactions and Coriolis forces. [ABSTRACT FROM AUTHOR]

A recently discovered tetraquark candidate having four distinct flavors is investigated using a first-order mass formula. This mass relationship is based on weakly bound meson clusters and provides a reasonable prediction for the measured X(5568) tetraquark mass. The possible discovery of a 750 GeV/c² state is also represented reasonably well by the first-order tetraquark mass formula incorporating a tttt structure. [ABSTRACT FROM AUTHOR]

Several important equilibrium Si isotope fractionation factors among minerals, organic molecules and the HSiO solution are complemented to facilitate the explanation of the distributions of Si isotopes in Earth's surface environments. The results reveal that, in comparison to aqueous HSiO, heavy Si isotopes will be significantly enriched in secondary silicate minerals. On the contrary, quadra-coordinated organosilicon complexes are enriched in light silicon isotope relative to the solution. The extent of Si-enrichment in hyper-coordinated organosilicon complexes was found to be the largest. In addition, the large kinetic isotope effect associated with the polymerization of monosilicic acid and dimer was calculated, and the results support the previous statement that highly Si-enrichment in the formation of amorphous quartz precursor contributes to the discrepancy between theoretical calculations and field observations. With the equilibrium Si isotope fractionation factors provided here, Si isotope distributions in many of Earth's surface systems can be explained. For example, the change of bulk soil δSi can be predicted as a concave pattern with respect to the weathering degree, with the minimum value where allophane completely dissolves and the total amount of sesqui-oxides and poorly crystalline minerals reaches their maximum. When, under equilibrium conditions, the well-crystallized clays start to precipitate from the pore solutions, the bulk soil δSi will increase again and reach a constant value. Similarly, the precipitation of crystalline smectite and the dissolution of poorly crystalline kaolinite may explain the δSi variations in the ground water profile. The equilibrium Si isotope fractionations among the quadra-coordinated organosilicon complexes and the HSiO solution may also shed light on the Si isotope distributions in the Si-accumulating plants. [ABSTRACT FROM AUTHOR]

A particular quantum phase transition (QPT) is studied at excited energies of light nuclei within the Semimicroscopic Algebraic Cluster Model (SACM), using a combination of catastrophe theory and a direct minimization of the potential. A distinct change from a compact nucleus to a nuclear molecule is described as a second order QPT occurring at a certain value of angular momentum. This finding is in accordance with experimental observations when nuclear molecules appear. The method has implication in the fission of heavy nuclei. [ABSTRACT FROM AUTHOR]

We tentatively investigate the root-mean-square (rms) nuclear charge radii of odd- A Po and Pb isotopes plus Tl isotopes, particularly concerning these difficultly-detected nuclei along with short lifetimes, via various data on α decay. Within the density-dependent cluster model, the density distributions of studied daughter nuclei are determined by exactly reproducing the corresponding experimental α decay half-lives, which leads the final results of nuclear charge radii. In addition, our recently proposed formula deducing the charge radii is extended to this study for comparison. Whether it concerns the ground or isomeric state of target nuclei, the extracted nuclear charge radii are found to be in good agreement with the measured values. Sequential predictions on the rms charge radii are subsequently made for these neutron-deficient nuclei and especially for the rarely detected Bi isotopic chain, which are expected to be useful for future measurements. Moreover, the variety of α -preformation factors is analyzed in the scheme of valence nucleon number to pursue the further improvement of the model. This may be considered as an effective effort to obtain the charge radii of ground and even low-lying excited states for exotic nuclei near the proton-dripline. [ABSTRACT FROM AUTHOR]

Applying the R. A. Brightsen Nucleon Cluster Model of the atomic nucleus we discuss how stable and unstable unmatter entities (the conjugations of matter and antimatter) may be formed as clusters inside a nucleus. The model supports a hypothesis that antimatter nucleon clusters are present as a parton (sensu Feynman) superposition within the spatial confinement of the proton (¹H1), the neutron, and the deuteron (¹H2). If model predictions can be confirmed both mathematically and experimentally, a new physics is suggested. A proposed experiment is connected to orthopositronium annihilation anomalies, which, being related to one of known unmatter entity, orthopositronium (built on electron and positron), opens a way to expand the Standard Model. [ABSTRACT FROM AUTHOR]

In the present study, we analyze the quasi-elastic scattering data of 17F + 12C reaction at 60 MeV using the cluster model, the optical model and the double folding model. We compare the theoretical results obtained for all the models with the experimental data. These comparison provide information about the similarities and differences of the models used in calculations. [ABSTRACT FROM AUTHOR]

Abstract: The structure of the 38Ar nucleus is investigated by the orthogonality condition model (OCM). The energy spectra, electromagnetic transitions and α spectroscopic factors are calculated. The excited states can be grouped into several bands according to the leading configurations of their wave functions, and the structures of the bands are discussed. The first excited band is found to be predominantly cluster states. It is also shown that the observed energies and E2 transitions of the band are well reproduced by the model. The existence of a negative-parity doublet band of the band is also predicted. The strength of the α-cluster states is shown to be spread over several levels due to mixing of shell-model states and various α-cluster states. [Copyright &y& Elsevier]

Abstract: An ensemble of ten silicate clusters is examined using quantum chemical calculations (Density Functional Theory) as a potential model to study the effect of polymerization of the SiO4 units on Raman intensities of silicates (crystalline and amorphous). Quite originally, instead of saturating non-bridging oxygen (NBO) with hydrogen atoms as generally found in the literature for similar approaches, NBOs, which hold a negative charge if not saturated, have been substituted by isoelectronic fluorines whose mass is corrected in normal mode calculations to be equal to that of an oxygen. By adjusting the number of fluorines per silicon, the different Qn coordination types characterizing the different classes of silicates are modeled. The relevance of this ensemble of clusters as a model to study the effect of polymerization on Raman intensities is established in several steps, the most important one being the qualitative reproduction of evolution of the Ip polymerization index with the number of bridging oxygen per silicon. [Copyright &y& Elsevier]

Recently discovered tetraquark structures are investigated using a first-order mass formula. This mass relationship is based on weakly bound ... plus dū meson clusters and provides a reasonable prediction of the measured Z(4430)- tetraquark mass. [ABSTRACT FROM AUTHOR]

The catastrophe theory is applied to a nuclear cluster model and an effective model for QCD at low energy. The study of quantum phase transitions in the cluster model was considered in an earlier publication, but restricted to spherical clusters and on a semi-classical level. In the present contribution, we include the case of deformed clusters and determine the spectrum numerically as a function of an interaction parameter, where signatures of a quantum phase transition can be seen. It is shown that in this more complicated case, with deformation of the clusters, the catastrophe theory can be applied with some interesting consequences. A further example of a many-body problem is considered, namely an effective model of QCD, which is able to describe the low energy hadron spectrum and, when temperature is introduced, even ratios of particle-antiparticle productions. The catastrophe theory is able to provide useful information on the phase transition from a perturbative to a non-perturbative vacuum. These contributions show the universal usefulness of catastrophe theory, while more examples of applications to different fields are mentioned in the Introduction. [ABSTRACT FROM AUTHOR]

In this proceeding, we present the results of the theoretical evaluations of the electric dipole moment (EDM) of light nuclei, including the preliminary value for the 11B nucleus. From the data, we can infer an approximate counting rule, and predict the EDM of other light nuclei. [ABSTRACT FROM AUTHOR]