| dc.description.abstract | The study of atomic nuclei is important in the context of in a wide variety
of applications, In particular, nuclear energy, nuclear medicine, and trace
element analysis etc. also, it is relevant in the context of astrophysical
applications, the stellar evolution, nucleosynthesis and in nuclear reactions. In
order to analyse the complete behaviour of a nucleus, based on experimental
results, different theoretical models are necessary.
Nowadays several
theoretical approaches are available in the literature, to explain the static
properties and collective behaviour of atomic nuclei. Single particle excitation
and collective excitation are the possible excitation modes in a nucleus.
The main objectives of this thesis work is to investigate the structure
properties of thorium nuclei lying on and off the valley of β-stability. The
studies can be broadly classified into two, aiming to understand the ground state
properties and the dynamic properties of thorium isotopes. For the structure
study, the nuclear level density is one of the important factors. The level density
of thorium nuclei were estimated by different phenomenological models of
level density. The nuclear structure properties like binding energy, charge radii,
rms radii and its isotopic shift, two-neutron separation energy and shell gap,
chemical potential, quadrupole deformation, density distribution and single-
particle energy of thorium nuclei, lying on and off the line of β-stability are
estimated.
This study will help us understand the variation of nuclear properties with
neutron number and to predict the shell closure and nuclear stability. Broken
linearities were observed at around neutron numbers N=126, 138 and 184 in the
plots of various evaluated values against neutron number. Single-particle energy
gaps were evaluated at around these neutron numbers. Large deviation and shell
gaps were observed at around the neutron numbers N=126 and 184. Hence,
these numbers are neutron magic numbers and the corresponding thorium
nuclei are more stable than their neighbours. A small deviation and shell gap
were observed at around N=138, and hence we conclude that this neutron
number is semi-magic and the associated nucleus is relatively stable. Most of
the thorium nuclei are of prolate shape. However, they are spherical at N=126
and 184. | en_US |
