Lifetime measurements of spherical and deformed states in 1f7/2 nuclei

Lifetimes have been determined using the Doppler Shift Attenuation Method in the N ≈ Z nuclei ⁴⁶V and ⁴⁸V, populated with the reaction ²⁸Si on ²⁴Mg at 115 MeV and ²⁴Mg on ²⁸Si at 100 MeV using Au and Pb backed targets. The coexistence of spherical and deformed states in the middle of the 1f_7/2 shell is discussed. The B(E2) and B(M1) reduced rates agree very well with large scale shell model predictions.     

Masses of nuclei

The study of masses of the different nuclear species is basic to the whole of nuclear physics. Because of the interchangeability of mass and energy the details of energy absorption or release are identical with mass differences or changes in the masses of participating nuclei. The systematic trends in mass value reflect therefore changes in the nuclear binding energy. It is one of the primary tasks of nuclear theory to explain the total binding energy of a lump of nuclear matter. The systematic trends in mass differences are also of basic importance in evolving models to describe the formation of the elements in our galaxy.     

Beta-delayed γ-ray studies of πf7/2 - νpf shell nuclei

We have utilized the selective process of β decay to populate low-energy excited states in the neutron-rich ₂₂Ti, ₂₃V, ₂₄Cr, and ₂₅Mn nuclei. The goal was to systematically track the monopole shift of the νf_5/2 single-particle level with increased occupancy of the πf_7/2 orbital. The β-decay properties of the parent nuclides, along with the low-energy structure of the daughters, are presented and compared with the results of shell model calculations employing the GXPF1 interaction.     

Core polarisation effect on the 3p 1/2, 3p 3/2, 2f 5/2, 2f 7/2 and 1i 13/2 proton states of209Bi

The weak fragments of the 3p_1/2, 3p_3/2, 2f_5/2, 2f_7/2 and 1i_13/2 proton states of²⁰⁹Bi as seen in the²⁰⁸Pb (³He,d) reaction can be explained with the coupling of the renormalised proton states and the vibrational states of²⁰⁸Pb. The energies of the zerothorder proton shell-model states as well as the collective admixtures of the weak fragmented proton states of²⁰⁹Bi have been deduced from the core-particle coupling model.     

Signature dependence of 1/2+ bands in rare-earth nuclei: Rotation-alignment of g7/2 protons

The origin of the signature splitting of theK=1/2⁺ bands in odd Z rare-earth nuclei Ho, Tm and Lu, unexplained in previous models, is studied by angular momentum projection from deformed Hartree-Fock configurations. Energy spectra,E2 matrix elements and the rotation-aligned angular momenta of nucleons in i_{1 3/2}, h_{1 1/2} and g_7/2 orbits are calculated. Staggering in the rotation-alignment of protons in the g_7/2 orbit causes signature dependent effects in the 1/2⁺ bands.     

Effects of core polarization and exchange currents on the magnetic form factors of 0f 7/2 and 0g 9/2-shell nuclei

We have studied core polarization and exchange current effects on the magnetic form factors with the highest multipolarities allowed by the shell model:M 7 for⁴⁹Ti,⁵¹V, and⁵⁹Co, andM9 for⁸⁷Sr and⁹³Nb. One-pion exchange currents partially remove discrepancies between density-dependent Hartree-Fock-Bogoliubov calculations and experiments.     

Collective bands of the positive parity states inf 7/2 shell nuclei

Collective bands of the positive parity states in odd-A f _7/2 shell nuclei are described in the framework of deformed Hartree-Fock theory by projecting states from lowest energy intrinsic states with (d ₃ ^2/−1 f ₇ ^2/n+1 ) one hole configurations. In the calculation empirical (d _3/2 −f _7/2)² effective matrix elements have been used to test the tacit assumptions of the Bansal and French model.     

Masses of atomic nuclei far from stability

It is shown that a new way of applying a set of nuclear-mass relations among neighbouring nuclei, known as the Garvey–Kelson (GK) relations, holds exceptionally well for all currently measured masses. It is then demonstrated that these relationships are not adequately fulfilled for the best-known procedures to predict unknown masses. This suggests that these models may be optimized by constraining them to satisfy the (generalized) GK equations.     

Simulation of 1/f noise spectra in YBa2Cu3O7 epitaxial films

A Monte Carlo simulation of the 1/f noise spectra in the normal phase of YBa₂Cu₃O₇ epitaxial films is reported. It is conjectured that the main contribution to the noise is from oxygen transitions to vacant sites in the CuO plane. It is shown that the annealing regime and the mismatch strains between the film and the substrate are the main factors governing the domain and defect structure of the film and, hence, the 1/f noise spectrum. Fiz. Tverd. Tela (St. Petersburg) 41, 957–964 (June 1999)     

On the microscopic description of the low-lying states in doubly even 2p-1f shell nuclei

The intrinsic states of doubly even Ti, Cr, Fe and Ni isotopes are obtained by carrying out HFB calculations employing a modified version of the Kuo-Brown effective interaction. The angular momentum projected spectra, the quadrupole moments of the first excited states as well as the reduced transition probabilities for E2 transitions are calculated and compared with the experiments. The overall agreement between the calculated and experimental results is quite good.     

Pu和Au原子4f5/2和4f7/2的结合能计算

基于Koopmans定理,应用MCDF方法计算了Pu和Au原子4f5/2和4f 7/2的结合能以及PuO2所引起的化学位移,一般大于固体的相应值.     

Static quadrupole moments and B(E2)(0 → 2) values in 2p-1f shell nuclei

The quadrupole moments of the first excited states and the reduced transition probabilities for E2 transitions in even-even Ti, Cr, Fe and Ni isotopes are calculated from the projected Hartree-Fock-Bogolubov wave functions in the 2p-1f shell. The overall agreement between the calculated and experimental results is quite good.