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

摘要

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 ~2Σ~+, ~2Π, and ~2Δ symmetries, dissociating up to Na (4d) + H~+ and Na~+ + H (3d), 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 ~2Σ~+ and ~2Π 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~2Σ~+ and the 2~2Σ~+ states to higher excited states of ~2Σ~+ and ~2Π symmetries. Finally, the adiabatic potential energy curves of the ground (X~2Σ~+) and the first (2 ~2Σ~+) excited states and the transition dipole moments between these states are used to evaluate the radiative lifetimes for the vibrational levels of the 2~2Σ~+ 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.