One‐electron pseudopotential study of the alkali hydride cation NaH + : Structure, spectroscopy, transition dipole moments, and radiative lifetimes

The structure and spectroscopic properties of the ground and the lowest excited electronic states of the alkali hydride cation NaH + have been investigated using an ab initio approach. In this approach, a nonempirical pseudopotential for the Na + core has been used and a core–core and a core‐valence correlation corrections have been added. The adiabatic potential energy curves and the molecular spectroscopic constants for numerous electronic states of 2 Σ + , 2 Π, and 2 Δ symmetries, dissociating up to Na (4 d ) + H + and Na + + H (3 d ), have been calculated. As no experimental data are available, we discuss our results by comparing with the available theoretical calculations. A satisfying agreement has been found for the ground state with previous works. However, a clear disagreement between this study and the model potential work of Magnier (Magnier, J. Phys. Chem. A 2005, 109, 5411) has been observed for several excited states. Numerous avoided crossings between electronic states of 2 Σ + and 2 Π symmetries have been found and analysed. They are related to the interaction between the potential energy curves and to the charge transfer process between the two ionic systems Na + H and NaH + . Furthermore, we provide an extensive set of data concerning the transition dipole moments from X 2 Σ + and the 2 2 Σ + states to higher excited states of 2 Σ + and 2 Π symmetries. Finally, the adiabatic potential energy curves of the ground (X 2 Σ + ) and the first (2 2 Σ + ) excited states and the transition dipole moments between these states are used to evaluate the radiative lifetimes for the vibrational levels of the 2 2 ∑ + state for the first time. In addition to the bound–bound contribution, the bound‐free term has been evaluated and added to the total radiative lifetime. © 2012 Wiley Periodicals, Inc.