High-Resolution Photoelectron Spectroscopy of the Ground and First Excited Electronic States of MgXe .

We report on the characterization of the X+ 2 Σ+ ground and the A+ 2 ΠΩ (Ω = 1/2, 3/2) and B+ 2 Σ+ electronically excited states of MgXe+ . Rotationally cold MgXe in the a 3 Π0 ( v ″ = 0) metastable electronic state was generated in a laser-ablation supersonic-beam source. Following single-photon excitation from the metastable state, the vibrational structure of the X+ state of MgXe+ was measured by pulsed-field-ionization zero-kinetic-energy photoelectron spectroscopy, and the adiabatic ionization energy of the X+ ← a ionizing transition was determined to be E I /( hc ) = 37,468.3(6) cm-1 . Spectra of the A+ ← X+ and B+ ← X+ transitions were recorded by using the method of isolated-core Rydberg-dissociation spectroscopy. The observation of the Mg+ (3p) 2 P1/2 + Xe 1 S0 dissociation limit enabled the determination of the dissociation energies of the X+ [ D 0 (X+ ) = 2970(7) cm-1 ] and A+ states [ D 0 (A1/2 + ) = 9781(7) cm-1 and D 0 (A3/2 + ) = 9603(7) cm-1 ]. We compare these results with those of earlier experimental studies and ab initio quantum-chemical calculations.