S. G. Rohoziński

Microscopic dynamic calculations of collective states in xenon and barium isotopes

Abstract Dynamic calculations of collective states for neutron-deficient doubly even Xe and Ba isotopes are performed. The collective Hamiltonian is constructed in terms of the cranking inertial functions and the macroscopic-microscopic potential, both generated by the single-particle motion in the modified harmonic oscillator potential. The pairing correlations are included. Reduction of the standard pairing interaction strengths leads to results compatible with experiment. The deformation dependence of the inertial functions is found to play an important role.

Quadrupole collective states within the Bohr collective Hamiltonian

The article reviews the general version of the Bohr collective model for the description of quadrupole collective states, including a detailed discussion of the models kinematics. The quadrupole coordinates, momenta and angular momenta are defined and the structure of the isotropic tensor fields as functions of the tensor variables is investigated. After a comprehensive discussion of the quadrupole kinematics, the general form of the classical and quantum Bohr Hamiltonian is presented. The electric and magnetic multipole moment operators acting in the collective space are constructed and the collective sum rules are given. A discussion of the tensor structure of the collective wavefunctions and a review of various methods of solving the Bohr Hamiltonian eigenvalue equation are also presented. Next, the methods of derivation of the classical and quantum Bohr Hamiltonian from the microscopic many-body theory are recalled. Finally, the microscopic approach to the Bohr Hamiltonian is applied to interpret collective properties of 12 heavy even–even nuclei in the Hf–Hg region. Calculated energy levels and E2 transition probabilities are compared with experimental data.

Local density approximation for proton-neutron pairing correlations: Formalism

In the present study we generalize the self-consistent Hartree-Fock-Bogoliubov (HFB) theory formulated in the coordinate space to the case which incorporates an arbitrary mixing between protons and neutrons in the particle-hole

Collective quadrupole excitations in the 50 < Z, N < 82 nuclei with the general Bohr Hamiltonian

(p\text{\ensuremath{-}}h)

Experimental test of the polarization direction correlation method (PDCO)

and particle-particle (

The low-lying quadrupole collective excitations of Ru and Pd isotopes☆

p\text{\ensuremath{-}}p

Point symmetries in the Hartree-Fock approach. I. Densities, shapes, and currents

or pairing) channels. We define the HFB density matrices, discuss their spin-isospin structure, and construct the most general energy-density functional that is quadratic in local densities. The consequences of the local gauge invariance are discussed and the particular case of the Skyrme energy-density functional is studied. By varying the total energy with respect to the density matrices the self-consistent one-body HFB Hamiltonian is obtained and the structure of the resulting mean fields is shown. The consequences of the time-reversal symmetry, charge invariance, and proton-neutron symmetry are summarized. The complete list of expressions required to calculate total energy is presented.

Study of the inertial functions for rare-earth nuclei

Abstract The general Bohr Hamiltonian is applied to a description of low-lying collective excitations in even-even isotopes of Te, Xe, Ba, Ce, Nd and Sm. The collective potential and inertial functions are determined by means of the Strutinsky method and the cranking model, respectively. A shell-dependent parametrization of the Nilsson potential is used. An approximate particle-number projection is performed in the treatment of pairing correlations. The effect of coupling with the pairing vibrations is taken into account approximately when determining the inertial functions. The calculation does not contain any free parameter.

Nuclei from the barium region: Nonaxial or gamma-soft?

Abstract The study of the polarization direction correlation method (PDCO) for γ quanta emitted from the nuclear states oriented in fusion-evaporation reactions is discussed with emphasis on making unique multipolarity assignments. The method is applied to the data coming from a typical experiment performed with the EUROGAM II array, where polarization-sensitive CLOVER detectors were used. The accuracy obtained in the experiment for the studied transitions was high enough to exclude, using the PDCO method, most of the ambiguities which occur if the assignments are made on the basis of angular correlation measurements alone.

PDCO: Polarizational-directional correlation from oriented nuclei

Abstract Quadrupole excitations of even-even Ru and Pd isotopes are described within a microscopic approach based on the general collective Bohr model which includes the effect of coupling with the pairing vibrations. The excitation energies and E2 transition probabilities observed in 104–114 Ru and 106–110 Pd are reproduced in the frame of the calculation containing no free parameters. Particularly interesting are 104 Ru and 106–110 Pd where good agreement to very rich information based on Coulomb excitation experiments is achieved.