Thermal stability of (MgO)12 dimers
College of Physics and Electronic Engineering, Northwest Normal
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Received in final form: 15 December 2011
Published online: 31 January 2012
The cagelike (MgO)12 clusters were suggested to assemble the low-density nanoporous crystalline phases by connecting in the edge-to-edge, tetragonal face-to-face and hexagonal face-to-face manners. The stabilities of the (MgO)12 dimers bound in the above manners are investigated using methods of molecular dynamics (MD) and density functional theory (DFT). The MD simulations show that the (MgO)12 dimer connected in the hexagonal face-to-face manner can transform to a group of the hexagonal tubelike structures, and the dimer connected in the tetragonal face-to-face manner can change to other isomers through a 2 × 4 × 6 slab structure. Both isomerizations do not require rearrangements of the ions and they occurs at about 700 K and 1000 K, respectively. The DFT calculations indicate that the energy barriers of the isomerizations are about 1 eV, which suggests a lower isomerization temperature.
Key words: Clusters and Nanostructures
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2012