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G. B. Vakil

Publications and source records attributed to G. B. Vakil.

4 recordsLinked to original sources

Microscopic investigation of the $I^π=8^-$ isomer decay in even-even N = 74 isotones

The microscopic approach of the triaxial projected shell model (TPSM) is employed to investigate the properties of the $8^-$ isomer in the six isotones of $^{128}$Xe, $^{130}$Ba, $^{132}$Ce, $^{134}$Nd, $^{136}$Sm, and $^{138}$Gd. The observed decay pattern of the isomer for these isotones is unexpected with the hindrance factor decreasing with atomic number. It is shown in the present work that multi-quasiparticle mixing into the ground-state configuration is responsible for the observed decreasing trend of the hindrance factor. We have also calculated the excitation energies and in-band $B(E2)$ transition probabilities of the yrast and the band built on the $8^-$ isomer for the six isotones, and it is shown that TPSM approach reproduces the measured quantities quite satisfactorily.

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Microscopic investigation of magnetic and antimagnetic rotational motion in atomic nuclei

In the present work, we have generalized the projected shell model (PSM) approach to include the quasiparticle excitations from two major oscillator shells, and have also extended the basis space to five-quasiparticle configurations for odd-mass nuclei. The magnetic and antimagnetic rotational structures observed in odd-neutron Pd- and Cd-isotopes have been investigated as a first major application of the new development. It is shown that PSM approach provides a reasonable description of the observed properties of magnetic and antimagnetic rotational bands.

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Microscopic investigation of wobbling motion in even-even nuclei

The possibility of observing wobbling mode in the even-even systems of 76Ge, 112Ru, 188,192Os, 192Pt and 232Th is explored using the triaxial projected shell model approach. These nuclei are known to have γ-bands whose odd-spin members are lower than the average of the neighbouring even-spin states. It is shown through a detailed analysis of the excitation energies and the electromagnetic transition probabilities that the observed band structures in these nuclei except for 232Th can be characterised as originating from the wobbling motion. It is further demonstrated that quasiparticle alignment is responsible for driving the systems to the wobbling mode.

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Triaxial projected shell model study of gamma-vibrational bands in even-even Er isotopes

We expand the triaxial projected shell model basis to include triaxially-deformed multi-quasiparticle states. This allows us to study the yrast and gamma-vibrational bands up to high spins for both gamma-soft and well-deformed nuclei. As the first application, a systematic study of the high-spin states in Er-isotopes is performed. The calculated yrast and gamma-bands are compared with the known experimental data, and it is shown that the agreement between theory and experiment is quite satisfactory. The calculation leads to predictions for bands based on one- and two-gamma phonon where current data are still sparse. It is observed that gamma-bands for neutron-deficient isotopes of 156Er and 158Er are close to the yrast band, and further these bands are predicted to be nearly degenerate for high-spin states.

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