Structures and Stabilities of Alkaline Earth Metal Oxide Nanoclusters: A DFT Study

Prinka Batra,Upasana Issar,Rita Kakkar,Ritu Gaba

doi:10.1155/2013/720794

Abstract

The stability orders of a number of alkaline earth oxide cluster isomers (MO)n, M = Mg, Ca, Sr, Ba and 1≤n≥6 have been determined by means of density functional theory studies using the LDA-PWC functional. Among the candidate structures, the hexagonal-ring-based isomers and the slab shapes are found to display similar stabilities. Stacks of hexagonal (MO)3 rings are found to be the slightly preferred growth strategy among the (MgO)6, isomers. In contrast, the slab structures are slightly preferred for the other alkaline metal oxide (MO)6 clusters. An explanation based on packing and aromaticity arguments has been proposed. This study may have important implications for modeling and understanding the initial growth patterns of small nanostructures of alkaline earth metals.

Highlights

In the last few years, considerable effort has been directed to the understanding of metallic and semiconductor clusters
We aim to study the electronic properties of the clusters of these alkaline earth metal oxides using the density functional approach
Various theoretical studies at different levels of calculations have been reported in the literature [1, 2, 29, 32, 40,41,42], but there is no clear consensus regarding the suitability of local density approximation (LDA), generalized gradient approximation (GGA), or hybrid functionals for calculations on metal oxide nanoclusters

Summary

Introduction

In the last few years, considerable effort has been directed to the understanding of metallic and semiconductor clusters. While much progress has been made on clusters of metals and semiconductors, metal oxide particles are often considered to be bulk fragments. Their structure and properties could be entirely different in small clusters [1,2,3,4]. The high surface area and the intrinsically high surface reactivity of MgO nanocrystals make these materials especially effective as adsorbents [6]. They have been called “destructive adsorbents” because of their tendency to adsorb and simultaneously destroy by bond breaking processes a series of toxic chemicals [6,7,8,9]

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Conclusion