Characterization of the 3dδ Rydberg state of MgAr+ using a quantum-control optical scheme

The authors developed a highly sensitive method based on a quantum-control double-resonance-spectroscopy scheme to study electronically excited states of molecular ions that do not dissociate. The method is used to study the $3d\phantom{\rule{0}{0ex}}\ensuremath{\delta}$ Rydberg state of MgAr${}^{+}$, and the results contribute to the first extensive characterization of the Rydberg states of a molecular cation.