Insights into the structures, energetics, and vibrations of aqua-rubidium(I) complexes: Ab Initio study.

We have carried out ab initio and density functional theory calculations of hydrated rubidium cations. The calculations involve a detailed evaluation of the structures, thermodynamic properties, and IR spectra of several plausible conformers of Rb⁺(H₂O)_n=1–8 clusters. An extensive search was made to find out the most stable conformers. Since the water-water interactions are important in hydrated Rb⁺ complexes, we investigated the vibrational frequency shifts of the OH stretching modes depending on the number of water molecules and the presence/absence of outer-shell water molecules. The predicted harmonic and anharmonic vibrational frequencies of the aqua-Rb⁺ clusters reflect the H-bonding signature, and would be used in experimental identification of the hydrated structures of Rb⁺ cation. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]