Theoretical Study of Structures and Spectral Properties of ScSnn0/−/2− (n = 4–17) Nanoalloy Clusters

Abstract

The ground-state structures of neutral, monovalent, and divalent anion ScSn_n^0/−/2− (n = 4–17) clusters were calculated by using a global search technique combined with density functional theory, and their spectral properties, electronic configurations, and relative stability were also studied. It is found that the ground-state structures for monovalent anion ScSn_n⁻ (n = 4–17) clusters are similar to those of divalent anions, and the ground-state structures for ScSn_n^−/2− are all adsorption structures obtained by adsorbing one Sn atom on the structures of ScSn_n−1^−/2−. The growth mode of ScSn_n^0/−/2− (n = 4–17) clusters can be divided into three different types of adsorption modes (n = 4–5, n = 6–10 and n = 11–17): ScSn₄^0/−/2− triangular bipyramid structures, ScSn₆^0/−/2− pentagonal bipyramid structures, and ScSn₁₁^0/−/2− single capped anti-pentagonal prism structures are used as base units to adsorb 1–6 Sn atoms, forming adsorption structures. When n = 11, it is the smallest cage structure size. The simulated photoelectron spectra of ScSn_n⁻ clusters are in good agreement with the existing experimental spectra. The infrared, Raman, and ultraviolet spectral properties of ScSn_n^0/−/2− (n = 4–17) clusters were analyzed, and their natural population analysis, dissociation energy, second-order energy difference, and HOMO-LUMO energy gap were also discussed. The results show that the FK-structure ScSn₁₆⁻ cluster not only has good thermodynamic stability and chemical stability, but also exhibits ideal optical properties, which can be used as a potential nano-optical material building block.