This thesis investigates the long-range interactions between Rydberg atoms and ions. Depending on the Rydberg state, the two particles may either collide or form a novel type of molecular bond, first observed in a cold rubidium gas within this study. The binding mechanism relies on the dipole moment of the Rydberg atom, which is induced by the ion, causing the dipole to change orientation around an equilibrium distance and bind the two partners. The binding length is notably large for a diatomic molecule, measuring approximately 2 μm to 4 μm for the examined vibrational states. Through photoassociation spectroscopy, several vibrational states are identified, with energy spacings aligning well with theoretical predictions. An ion microscope facilitates the spatially and temporally resolved observation of Rydberg-atom–ion pairs, revealing that the molecule's alignment can be controlled by the excitation laser's polarization. The findings on classical Rydberg-atom–ion collisions highlight the impact of highly polarizable Rydberg states on dynamics and showcase the microscope's potential for future ultracold quantum studies. With a resolution below 200nm, the ion microscope is adept at examining interactions and transport phenomena in bulk systems of Rydberg atoms, ultracold atoms, or ion-atom hybrid systems.
