Covariant density functional theory is used to analyse the response to the E1 and M1 electromagnetic transition operators in superfluid deformed nuclei in the framework of self-consistent Hartree-Bogoliubov theory and relativistic quasiparticle random phase (RQRPA) approximation. The fully self-consistent RHB+RQRPA equations are posed for the case of axial symmetry and for three different kinds of energy functionals, and solved with the help of a new parallel code. Special care is taken in order to validate the proper decoupling of spurious modes. Results of the first multipole magnetic operator (M1) response in light and heavy deformed nuclei are presented and analysed; in particular, the scissors mode and spin excitations. Qualitative agreement with experiment is obtained for the position of the scissors mode, and its structure as a rotation of the deformed neutron density against the deformed proton density reproduced. In addition to the scissors mode, a soft M1 mode with strong orbital character is found in heavy nuclei at relatively low energies. From the analysis of the proton and neutron transition densities in the intrinsic frame, and from the structure of the RQRPA amplitudes, it is concluded that this mode corresponds to a collective rotation of the deformed neutron skin against the deformed proton-neutron core. The response in light and heavy nuclei to the electric dipole operator (E1) is also given consideration. The position of the Giant Dipole Resonance is well reproduced within the RHB+RQRPA framework in axial symmetry. The effects of superfluidity and deformation on the Pygmy Dipole Resonance are closely examined. Excellent agreement with recent experimental results is found.
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AcknowledgementsFirst and foremost I would like to thank my supervisor, Prof. Dr. Peter Ring, not only for stimulating discussions and timely advice, but also for his support throughout the various phases of the work presented in this document. His understanding and experience in many areas has made a pleasure working with him. I am particularly grateful for his optimism and overall confidence in the project, always trying to point me on the right direction but giving me enough leeway to learn from my own mistakes.Many thanks go to Roger Hilton, who was always a source of good humour and interesting conversations while at the TUM. He patiently read the first drafts and helped me polish all the rough edges, both in the contents and in the use of the English language.It is a pleasure for me to thank all my colleagues at the TUM Theory Department and at the TUM campus in Garching, who have provided support and company during my time in Munich, with a special mention to