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[en] There exists a variety of nuclear structure phenomena within the chain of Zr isotopes in the low-excitation regime. While the ground state of 94Zr is spherical in nature, the occurrence of low-lying collective structure has also been observed. The excitation of protons across the Z = 40 sub-shell closure appears to playa dominant role for this collective structure in 94Zr. With the goal of looking for possible competition between proton and neutron excitations in 94Zr, an experiment was carried out at the TRIUMF-ISAC radioactive beam facility. The low-lying states of 94Zr were populated from the β- decay of 94Y. The 8π spectrometer was composed of 20 Compton-suppressed HPGe detectors; details of the experimental setup can be found in earlier literature. Combining the singles and coincidence data, a comprehensive level scheme of 94Zr has been constructed up to Ex ∼ 4.8 MeV, which is very close to the Qβ- value 4.918 MeV. With the revised level lifetimes and the newly found decay branches from the present investigation, the levels could be categorized in terms of proton and neutron excitations. Detailed results obtained from the analysis of the acquired data will be presented
[en] Ground state properties for Mg isotopes, including binding energies, one- and two-neutron separation energies, pairing energies, nuclear matter radii and quadrupole deformation parameters, are obtained from the selfconsistent relativistic mean field(RMF) model with the pairing correlations treated by a shell-mode-like approach(SLAP), in which the particle-number is conserved and the blocking effects are treated exactly. The experimental data, including the binding energies and the one- and two-neutron separation energies, which are sensitive to the treatment of pairing correlations and block effects, are well reproduced by the RMF + SLAP calculations. (authors)
[en] Configuration-constrained potential-energy-surface calculations have been performed to investigate the K isomerism in the proton-rich A ∼ 80 mass region. An abundance of high-K states are predicted. These high-K states arise from two and four-quasi-particle excitations, with Kπ= 8+ and Kπ = 16+, respectively. Their excitation energies are comparatively low, making them good candidates for long-lived isomers. Since most nuclei under study are prolate spheroids in their ground states, the oblate shapes of the predicted high-K states may indicate a combination of K isomerism and shape isomerism. (authors)
[en] A central ΛN potential VΛN that describes, in the limits of experimental errors, the binding energies of three-, four-, and five-particle ground and excited states of hypernuclei, as well as energy and angular dependence of Λp scattering cross sections, is found on the basis of a conjoint analysis of binding energies of 1s-shell hypernuclei and Λp scattering. The reliability and accuracy of three-, four-, and five-particle calculations of hypernuclei and related nuclear systems are assured by the estimation of, an upper, as well as a lower bound of energy. In the framework of the model Λ+core, VΛN agrees with binding energies of heavy hypernuclei.
[en] The strontium (Sr) isotopes with A ≤ 88 shows a gradual transition from the nearly double magic 88Sr nucleus to the rotational like behaviour in the 80Sr nucleus. Many collective bands have been seen in isotopes of Sr, Zr and Mo nuclei. The 84Sr isotope, which has four neutron holes lying in the 1g9/2; 2p1/2 and 1f5/2 sub shells, displays both collective and particle excitations. In the present experiment, the excited stated of 84Sr nucleus were studied to confirm the tentatively assigned spin to various previously known states and to search interesting high-spin phenomena in this mass region include Super deformation, loss of collectively, band termination, chiral rotation, and shape-related effects. The excited states of 84Sr nucleus was populated through the reaction 76Ge(12C,4n)84Sr, with a beam energy of 58 MeV which was provided by the 15-UD Pelletron at Inter University Accelerator centre (IUAC), New Delhi. The gamma-rays were detected by using the INGA spectrometer at IUAC which consisted of 18 Compton-suppressed clover detectors with four, four, six, two and two number of detectors placed at angles 148°, 123°, 90° 57° and 32° with respect to the beam direction, respectively, at the time of the experiment. The symmetric and asymmetric matrices were generated by sorting the data with the CANDLE and RADWARE programme. The spin and parity of the levels were assigned using the angular distribution, RDCO and polarization measurements. (author)
[en] The ground state nuclear structure properties of some proton rich even-even tellurium isotopes are studied by using Gogny energy density functional within the framework of Hartree-Fock-Bogoliubov (HFB) method. The HFB equations are solved by using the axial cylindrical transformed deformed harmonic oscillator basis. The full parameterization of Gogny energy density functional is employed in the present study. The evolution of the neutron density distributions with an increase in neutron number is studied and emergences of various nuclear structure phenomena are investigated. Besides this, the ground state nuclear structure properties such as nuclear multipole moments, deformation parameters, binding energies, pairing energies, root mean square radii and charge radii are obtained for even-even proton-rich tellurium isotopes. The theoretical results on ground state nuclear properties are compared with the available experimental data and good agreement with the experimental data is found. (author)
[en] The kinetic theory is applied to the nuclear Fermi liquid. The nuclear collective dynamics is treated in terms of the observable variables: particle density, current density, pressure etc. The influence of Fermi-surface distortion, relaxation processes and memory effects on the nuclear dynamics is studied. We show that the presence of the dynamic Fermi-surface distortion gives rise to some important consequences in the nuclear dynamics which are absent in classical liquids. We discuss the nuclear small amplitude excitations, the spinodal instability, the nuclear fission and the bubble instability in heated Fermi-liquid in presence of the memory effects.
[en] Within the framework of the dinuclear system (DNS) model, the fusion reactions leading to the compound nuclei 274Hs* and 286Cn* are investigated. The fusion probability as a function of DNS excitation energy is studied. The calculated results are in good agreement with the available experimental data. The obtained results show that the fusion probabilities are obviously enhanced for the reactions located at high place in potential energy surface, although these reactions may have small values of mass asymmetry. It is found that the enhancement is due to the large potential energy of the initial DNS. (authors)
[en] Nuclear mass contains a wealth of nuclear structure information, and has been widely employed to extract the nuclear effective interactions. The known nuclear mass is usually extracted from the experimental atomic mass by subtracting the masses of electrons and adding the binding energy of electrons in the atom. However, the binding energies of electrons are sometimes neglected in extracting the known nuclear masses. The influence of binding energies of electrons on nuclear mass predictions are carefully investigated in this work. If the binding energies of electrons are directly subtracted from the theoretical mass predictions, the rms deviations of nuclear mass predictions with respect to the known data are increased by about 200 keV for nuclei with Z, N ≥ 8. Furthermore, by using the Coulomb energies between protons to absorb the binding energies of electrons, their influence on the rms deviations is significantly reduced to only about 10 keV for nuclei with Z, N ≥ 8. However, the binding energies of electrons are still important for the heavy nuclei, about 150 keV for nuclei around Z = 100 and up to about 500 keV for nuclei around Z = 120. Therefore, it is necessary to consider the binding energies of electrons to reliably predict the masses of heavy nuclei at an accuracy of hundreds of keV. (authors)