Interaction of N2, O2 and H2 Molecules with Superalkalis

N₂ (blue), O₂ (red) and H₂ (grey) interact differently with superalkali clusters. Their interaction varies from strong covalent to weak van der Waals interaction leading to the possibility of reduction or adsorption of these small molecules.

Abstract

Superalkalis (SAs) are exotic clusters having lower ionization energy than alkali atoms, which makes them strong reducing agents. In the quest for the reduction of diatomic molecules (X₂) such as N₂, O₂, and H₂ using Møller-Plesset perturbation theory (MP2), we have studied their interaction with typical superalkalis such as FLi₂, OLi₃, and NLi₄ and calculated various parameters of the resulting SA−X₂ complexes. We noticed that the SA−O₂ complex and its isomers possess strong ionic interaction, which leads to the reduction of O₂ to O₂ ⁻ anion. On the contrary, there are both ionic and covalent interactions in SA−N₂ complexes such that the lowest energy isomers are covalently bonded with no charge transfer from SA. Further, the interaction between SA and H₂ leads to weakly bound complexes, which results in the adsorption of H₂ molecules. The nature of interaction is found to be closely related to the electron affinity of diatomic molecules. These findings might be useful in the study of the activation, reduction, and adsorption of small molecules, which can be further explored for their possible applications.

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