Dual External Field Strategy in Regulating the Superhalogen Characteristics of the Non-Noble Metal Constituted Tantalum Oxide Clusters

Abstract

The identification of the non-noble metal constituted TaO cluster as a potential analogue to the noble metal Au is significant for the development of tailored materials. It leverages the superatom concept to engineer properties with precision. However, the impact of incrementally integrating TaO units on the electronic configurations and properties within larger TaO-based clusters remains to be elucidated. By employing the density functional theory calculations, the global minima and low-lying isomers of the Ta_nO_n (n = 2–5) clusters were determined, and their structural evolution was disclosed. In the cluster series, Ta₅O₅ was found to possess the highest electron affinity (EA) with a value of 2.14 eV, based on which a dual external field (DEF) strategy was applied to regulate the electronic property of the cluster. Initially, the electron-withdrawing CO ligand was affixed to Ta₅O₅, followed by the application of an oriented external electric field (OEEF). The CO ligation was found to be able to enhance the Ta₅O₅ cluster’s electron capture capability by adjusting its electron energy levels, with the EA of Ta₅O₅(CO)₄ peaking at 2.58 eV. Subsequently, the introduction of OEEF further elevated the EA of the CO-ligated cluster. Notably, OEEF, when applied along the +x axis, was observed to sharply increase the EA to 3.26 eV, meeting the criteria for superhalogens. The enhancement of EA in response to OEEF intensity can be quantified as a functional relationship. This finding highlights the advantage of OEEF over conventional methods, demonstrating its capacity for precise and continuous modulation of cluster EAs. Consequently, this research has adeptly transformed tantalum oxide clusters into superhalogen structures, underscoring the effectiveness of the DEF strategy in augmenting cluster EAs and its promise as a viable tool for the creation of superhalogens.