Study of Gamow-Teller transitions under astrophysical conditions

In this thesis study, the B(GT)- and B(GT)+ strength distributions, total B(GT)- and B(GT)+ values, the centroid and width values in β^- and β^+ directions have been calculated for 40-60Ti, 42-65Cr and 50-78Ni isotopes in order to study the GT transition properties of fp nuclei which play on important role on astrophysical events such as supernova explosion and star collapse. In calculations, Schematic Method (SM), Pyatov Method (PM) and proton-neutron Quazi Particle Random Phase Approximation (pn-QRPA) method have been used as different QRPA methods. These methods have been divided into three subcategories. In A model, the shape of nucleus has been accepted as spherical and particle- hole interactions (ph) have been considered (spherical, ph). In model B, only particle-particle (pp) interactions have been added (spherical, ph+pp). In model C, the shape of nucleus has been considered as deformed and pp interactions have also been taken into account. In calculations for 40-60Ti, 42-65Cr and 50-78Ni isotopes, at the first stage, the calculations results for B(GT)- and B(GT)+ have been presented and compared with the corresponding experimental and other theoretical model results. Then, total B(GT)- and B(GT)+ values, energy centroid and width values in β^- and β^+ directions have been shown in Tables. As a result of calculations, we have observed that pp interactions and nuclear deformation have an increasing or decreasing effect on the number of GT 1+ states and the B(GT)- and B(GT)+ values. They have also provided the collection of GT 1+ state at a certain energy region and the distribution of these states over a wide energy range.