The study of so-called ‘deformed’ atomic nuclei with a non-spherical charge distribution is essential for testing nuclear interactions and structural models. These deformed nuclei exhibit a very particular pattern of excited states, known as ‘rotational bands’. These bands can be constructed on states with different deformations or different intrinsic structures (shape coexistence). The subject of the thesis is the experimental study of the macroscopic and microscopic properties of the nucleus 232Th. This nuclide exhibits a wide variety of rotational bands that are thought to be due to vibrations of the nuclear surface known as quadrupole and octupole vibrations. In particular the latter have attracted a great deal of interest recently, as octupolar deformed nuclei can be used to determine nuclear electric dipole moments, a fundamental question in physics in general. In our particular case, the aim is to characterise for the first time the quadruplet of octupole bands expected in a strongly deformed nucleus. Furthermore, this nucleus is the only example with a rotational band built on a double quadrupole vibration. A comprehensive characterisation of the excitation scheme of 232Th will also be of interest with regard to its gamma emissions as a possible future reactor fuel.

We will study these various shapes using the powerful technique of Coulomb excitation, which is the most direct method for determining the shape of nuclei in their excited states. The experiment will be carried out using AGATA, a new-generation gamma spectrometer consisting of a large number of finely segmented germanium crystals, which can identify each point of interaction of a gamma ray inside the detector and then, using the innovative concept of ‘gamma-ray tracking’, reconstruct the energies of all the gamma rays emitted and their emission angles with unprecedented precision. A complementary experiment will be carried out at HIL Warsaw, which will enable better interpretation of the highly complex data provided by AGATA.

This project investigates the structure and reactions of exotic atomic nuclei near the limits of stability, where nuclei may be weakly bound or unbound. Recent advances in radioactive-ion-beam technology enable experimental study of these rare systems, which often exhibit unusual features such as extended “halo” structures. Traditional nuclear models, effective for stable nuclei, fail to capture the complexities of these open quantum systems. To address this, the project develops and applies the Gamow Shell Model (GSM) and its extension to coupled-channel (GSM-CC) approaches, which treat nuclei as open systems able to exchange particles and energy with their environment. This enables a unified description of both nuclear structure and reactions, including the effects of the quantum continuum that become significant near the driplines. These models yield accurate predictions that align with experimental data, guide future research, and remain flexible enough to apply to areas such as hypernuclei, atomic anions, and engineered quantum systems. A key innovation is integrating structure and reaction theories, overcoming traditional divisions in the field. The frameworks are designed for computational efficiency and scalability, leveraging supercomputing resources and incorporating uncertainty quantification for reliable predictions. The project also fosters international collaborations with leading experimental facilities and contributes to the training of young scientists. By bridging gaps between theory and experiment, structure and reactions, and across quantum sciences, this research advances understanding of matter under extreme conditions, with broad implications for fundamental science and emerging technologies.