The project is focused experimental investigation of the Quadrupole-collective isovector valence-shell excitations, so-called mixed-symmetry states (MSSs) in stable and radioactive nuclei. No MSSs have been identified up to now in radioactive nuclei and their evolution with deformation is still unrevealed. We propose to investigate these phenomena in the mass A=90 and A=130 regions, extending the search for MSSs to unstable nuclei. This will expand the current knowledge to new, unexplored regions and can be considered as a part of the efforts to keep the European leadership in nuclear structure research. The mechanism of shell stabilization of MSSs in the radioactive N = 80 nuclei will be studied. Identifications of the one-phonon MSSs in these nuclei will be done in series of experiments at REX-ISOLDE (CERN). The evolution of one-phonon MSSs with deformation on both the transitions from vibrational to gamma-soft nuclei and from spherical vibrators to axially-symmetric rotors will be investigated in series of experiments at Argonne National Laboratory, USA. The nature of the MSSs cannot be completely revealed without information on their magnetic moments and more data on the two-phonon MSSs. To address these problems we will develop new methods which will be tested in experiments with stable nuclei. Identification of the two-phonon MSSs in radioactive nuclei is a task which is beyond the capabilities of the nowadays experimental facilities but will be in the reach of the next generation European Radioactive Ion Beams (RIBs). Developing techniques which can be utilized at the future RIBs facilities will ensure the sustainable development of the Nuclear Structure Group at SU St. Kl. Ohridski. Graduate and undergraduate students involvement will be the most significant broader impact of this project. Students will be involved in all parts of the project. The opportunity to use world-class facilities and to contribute to the frontier research will provide them with international experience which is of importance for their development either in science, or in the business.