Investigation of magnetic dipole excitations in even-even pseudo-mirror nuclei in the 150<A<170

Determination of the atomic nucleus's structure is a pivotal focus of nuclear physics, addressing essential topics such as the binding interactions among nucleons. The most reliable information in this field is obtained by rigorously evaluating the nucleus's response to external influences. Leading nuclear research centers worldwide, including CERN, INFN, GSI, and HILL, have conducted extensive and impactful studies over many years. These excitations culminate in the generation of level diagrams for each nucleus, with dipole excitation standing out as a crucial feature. Dipole excitations are of paramount interest in nuclear structure physics and are actively pursued by researchers employing a variety of theoretical frameworks and by experimentalists alike. As technology continues to advance, especially in experimental contexts, the nature of excitations reaching the MeV energy scale is becoming increasingly significant. Dipole excitations are precisely classified according to their spin and parity values. Notably, magnetic dipole excitations possess a spin (I) of Iπ=1+ and specific parity (π). A critical characteristic of these excitations is the observed transitions between spin-orbit pairs of neutron-neutron or proton-proton levels. Analyses of more than 3,000 nuclides found in the chart of nuclides reveal that nuclei have both different and common features. Recent studies have convincingly shown that nuclei paired as pseudo-mirror nuclei (PMN) with particle-hole symmetry in the level diagrams of nuclei are degenerate at low energy levels, especially quadrupole transitions. In studies looking at the energy systems of these nuclei, it has been observed that the system is easier to understand when examining the E(4+)/E(2+) energy values of PMN nuclei according to the NpNn number. The NpNn quantity is found by multiplying the Nn neutron particle or vacancy counted from the nearest closed shell by the Np proton particle or vacancy. The NpNn quantity is also a measure of the neutron-proton interaction, which is the effect that causes deformation behind the closed shell. This method claims that if the E(4+)/E(2+) ratios of nuclei with the same NpNn number are the same, their nuclear structures are similar. To reach this conclusion, the quantities E(2+), E(4+)/E(2+), and B(E2; 2+→0+) were analyzed for many nuclei in the nuclear chart, considering subclosed shells. A systematic approach was developed. The NpNn system is mainly based on the idea of particle-hole symmetry, and there is no consistent pattern when calculating NpNn using either hole-hole or particle-particle numbers. These scaling properties clearly show how important the proton-neutron force is between pairs of protons and neutrons, whether they are considered as particles or holes. There is no detailed study of this mutual similarity seen at lower energy levels of the level schemes of PMN pairs for higher energy excitations. The aim of this thesis is to rigorously investigate the possibility that the similarity observed in the low-energy quadrupole transitions of PMN pairs of nuclei is also present in the magnetic dipole B(M1;0+ →1+) transitions. Firstly, PMN nucleus pairs were determined by considering the NpNn numbers and E(4+)/E(2+) ratios of the nuclei located in the 150