Theoretical Study on Polynuclear Superalkali Cations with Various Functional Groups as the Central Core

Abstract

A new series of polynuclear superalkali cations YLi₃⁺ (Y = CO₃, SO₃, SO₄, O₄, and O₅) has been created when the central group is surrounded by alkali atoms. The structural characteristics and stabilities of these systems are provided on the basis of ab initio methods. In the lowest-energy structure of the CO₃Li₃⁺, SO₃Li₃⁺, and SO₄Li₃⁺ cations, the central Y (Y = CO₃, SO₃, and SO₄) group features a slight distortion. The global minima of O₄Li₃⁺ and O₅Li₃⁺ are of the forms O₂^–(Li⁺)₃O₂^– and O₂^–(Li⁺)₃O₃^–, respectively, both of which contain two monovalent ion units. The structural integrity of the central Y group and the arrangement of the lithium ligands are two influencing factors on the vertical electron affinities (EA_vert) for the YLi₃⁺ species. The YLi₃⁺ cation, with its lithium ligands being distributed evenly or far from each other, tends to exhibit a low EA_vert value, whereas a greater extent of cleavage of the central Y group leads to a higher EA_vert value and even makes some species lose their superalkali nature