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Negative ions hold significant interest because of their importance in understanding electron correlation. Further, they capture substantial focus for their role in, for example: stellar environments, medical applications, antimatter research, and accelerator mass spectrometry (AMS).This thesis covers experimental studies of both the structure anddynamics of negative ions at the ion beam facilities DESIREE (DoubleElectroStatic Ion Ring ExpEriment), CERN-ISOLDE (Isotope SeparatorOnLine DEvice) and GUNILLA (Gothenburg University Negative Ionand Laser LAboratory).At DESIREE, the electron affinites (EA) for the three stable isotopes of silicon have been measured with high precision, using lasermanipulation of quantum-state populations followed by laser photodetachment threshold (LPT) spectroscopy. The corresponding isotope shiftsin the EA have been calculated. Additionally, the hyperfine splitting ofthe ground state in 29Si− was measured.The EA for two radioactive isotopes, 128I and 211At, have beendetermined using LPT spectroscopy with the GANDALPH (GothenburgANion Detector for Affinity measurements by Laser PHotodetachment)detector at ISOLDE. These are the first ever EA measurements ofradioactive isotopes. This opens up a whole new field of experimentswhere the EA of even heavier ions can be measured, and giving thepossibility of measuring isotope shifts in radioactive isotopes.At the ion beam facility GUNILLA at the University of Gothenburg,the EA for rubidium has been measured using a state selective detectionof the residual atom in the LPT processes. If this selective measurementtechnique is combined with the possibility of studying radioactive beamsat ISOLDE, it can be applied to studies of rare anions, like francium.In terms of dynamical properties, the radiative lifetimes of excitedstates in several atomic and molecular anions have been measured atDESIREE and some previously unobserved energy states have beendetected. The methods used for detailed studies of the structure ofnegative ions used in this work lay the foundation for the ultimate goalto map out the lifetimes of all the excited states in negative ions.The research presented in here shows that it is only by combiningstructural and dynamical experimental results that it is possible toobtain a complete picture of negative ions. The results shown so farhave been used to benchmark theoretical methods, but there are stillquite a few discrepancies. By applying the methods used in this workto the full range of elements in the periodic table, and comparing themwith theoretical results, it will be possible to enhance our understandingof electron correlation. Of particular interest will be to study the veryheavy systems, where relativistic effects play a decisive role. |