Density functional study of structural and electronic properties of cube-like MgO clusters

Crossover between ionic-covalent bonding and pure ionic bonding in magnesium oxide clusters

“…This is also in agreement with the findings of Veliah et al 6 The above results confirm that conventional potentials with fixed charges are not fully appropriate to describe MgO clusters. This had been addressed by Wilson who considered phenomenological coordinationdependent polarizabilities within the compressible-ion model.…”

“…First, the magnitude of the charge transferred increases with coordination, as expected from the decreasing intensity of the electric field. This is in agreement with the electronic structure calculations performed by Recio et al, 3 by Veliah et al, 6 and more recently by Coudray et al…”

“…In the intermediate sizes regime, (MgO) n clusters are thus expected to show intriguing properties due to a partially covalent character of the chemical bonding. Beyond condensed matter or molecular physics, these clusters received some special attention in the astrophysics community, where they have been involved in the nucleation process of dust in circumstellar shells around M-stars.Despite the vast amount of experimental 2,4,5 and theoretical 2,3,6,7,8,9,10,11,12 investigations on neutral or charged clusters, the way and the rate at which chemical bonding evolves from ionic/covalent at small sizes toward purely ionic in the bulk remains essentially unexplored. Because the electrostatic field created by the ions does not vanish in finite systems, the highly polarizable oxyde anion has a rather floppy and deformable outer electron cloud, which could be responsible for a partial screening of the repulsion between cations.…”

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

“…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 LDA, GGA, or hybrid functionals for calculations on metal oxide nanoclusters. We therefore first compared results for the MgO molecular form obtained by different methods with the experimental quantities.…”

Spin-polarized ground states and ferromagnetic order induced by low-coordinated surface atoms and defects in nanoscale magnesium oxide

“…As for nanoscale oxides, the possible effect of these surface atoms may not be completely neglected. Furthermore, it has been demonstrated that the low-coordinated surface sites such as terraces, edges, and corners are more stable locations for atomic defects than the bulk sites because the formation energy of atomic defects will decrease with decreasing the number of surrounding atoms [18,19]. This allows one to expect that these low-coordinated surface states could potentially contribute to the generation of defect-related ferromagnetism in nanoscale oxide, as suggested by recent observations [6,8,20].…”