Systematic trends in electronic properties of alkali hydridesThis article is part of a Special Issue on Spectroscopy at the University of New Brunswick in honour of Colan Linton and Ron Lees.

Abstract

Obtaining ultracold samples of dipolar molecules is a current challenge, which requires an accurate knowledge of their electronic properties to guide the ongoing experiments. Alkali hydride molecules have permanent dipole moments significantly larger than those of mixed alkali species, and, as pointed out by Taylor-Juarros et al. (Eur. Phys. J. D, 31, 213 (2004)) and by Juarros et al. (Phys. Rev. A, 73, 041403 (2006)), are thus good candidates for cold molecule formation. In this paper, using a standard quantum chemistry approach based on pseudopotentials for atomic core representation, large Gaussian basis sets, and effective core polarization potential, we systematically investigate the electronic properties of the alkali hydrides LiH to CsH, to discuss general trends of their behavior. We computed (for the first time for NaH, KH, RbH, and CsH) the variation of their static polarizability with the internuclear distance. Moreover, in addition to potential curves, we determine accurate values of permanent and transition dipole moments for ground and excited states depending on the internuclear distance. The electronic properties of all alkali hydrides are compared with one another, in the light of the numerous other data available in the literature. Finally, the influence of the quality of the representation of the hydrogen electronic affinity in the approach on the results is discussed.