Rani Devi

Projected shell model study of the yrast bands of neutron-deficient 126–130Ce isotopes

The yrast bands of neutron-deficient 126–130Ce nuclei are studied by using the projected shell model approach. Energy levels, moments of inertia and B(E2) transition probabilities are calculated and compared with the available experimental data. The first and second backbending in 128,130Ce are investigated. The question as to why the backbending becomes sharp as the neutron number increases in cerium isotopes is addressed. It turns out that the first backbending is caused by a proton pair and the second backbending in 128,130Ce is due to a simultaneous proton and neutron pair breaking.

E2 transition and QJ+ systematics of even-mass ruthenium nuclei

The yrast spectra with Jmaxpi = 10+, B(E2) transition probabilities and QJ+ values are calculated for even-even ruthenium isotopes by carrying out variation after projection (VAP) calculations in conjunction with the Hartree-Fock-Bogoliubov (HFB) ansatz employing a pairing-plus-quadrupole-quadrupole effective interaction operating in a reasonably large valence space outside the 76Sr core. Our calculations describe the shape changes as a function of mass number for ruthenium isotopes and also reveal that both the HFB technique as well as the quadrupole-plus-pairing-quadrupole model of the two-body interaction are fairly reliable in this mass region.

A study of neutron-deficient 122–128Ba isotopes in the projected shell model framework

The projected shell model calculational framework is employed here for studying the nuclear structure determining properties such as high-spin yrast spectra, B(E2) transition probabilities and g-factors for neutron-deficient 122–128Ba isotopes. It turns out that a dip in B(E2) values and a peak in g-factors are correlated with crossing of the ground state band by multi-quasiparticle bands and alignment of a pair of protons in 1h11/2 subshell.

Study of 242−248Cm isotopes in the projected shell model framework

The projected shell model framework is employed to study the band spectra in 242−248Cm isotopes. The present calculations reproduce the available experimental data on the yrast bands. Besides this, B(E2) transition probabilities of even–even Cm isotopes have also been calculated. The low spin states of yrast band are seen to arise purely from zero-quasi-particle (o-qp) intrinsic states whereas the high spin states have multi-quasi-particle structure. For the odd-neutron (odd-N) isotopes, the calculated results qualitatively reproduce the available data on ground and lowest excited state bands for 243,245Cm. However, for 247Cm the negative-parity ground state band is in reasonable agreement with the experimental data.

Axial and non-axial study of neutron rich Pd and Cd isotopes near A = 120

Yrast energy levels and backbending phenomenon of neutron-rich Pd and Cd nuclei near A = 120 are studied by non-axial Cranked Hartree Bogoliubov (CHB) and axial projected shell model (PSM) approaches. The observed backbending in 118Pd is reproduced by both the approaches. The observed backbending in 120,122Cd is seen to be reproduced by the projected shell model approach by taking prolate deformation. The backbending in these nuclei may be due to the crossing of ground state band by two quasi-particle 1h11/2 neutron bands.

Study of band structure of neutron-rich Pr isotopes

The newly established bands in 151,153Pr are studied by using projected shell model approach. The calculated level scheme is in good agreement with the experimental data and the reflection-symmetric-quasi-particle rotor model. The present calculations predict proton g9/2, K = 9/2 band as the lowest positive parity band in both the nuclei.

Microscopic study of yrast band structures in {sup 66-72}Ge isotopes

High spin properties of the neutron-deficient {sup 66-72}Ge isotopes have been studied using the projected shell model approach. In particular, backbending phenomena, B(E2) transition probabilities, and g factors are investigated for these isotopes along the yrast line.

Microscopic study of deformed neutron-deficient 124-132Ce isotopes

Variation after Projection (VAP) calculations in conjunction with Hartree Bogoliubov (HB) ansatz have been carried out for 124-132Ce mass chain. In this framework, the yrast spectra, B(E2) transition probabilities and occupation numbers for various shell model orbits have been obtained. The observed decrease in deformation in going from 124Ce to 132Ce is seen to arise due to a slow decrease in the occupation of 1g7/2 proton orbit and a systematic increase in the occupations of 2d5/2, 1g7/2 and 1h11/2 neutron orbits. Besides this, the experimental low-lying yrast spectra and B(E2) transition probabilities are reproduced with reasonable accuracy by using PQOH interaction.