Structure Prediction of Ternary Oxide Sub-Nanoparticles.
MATER MANUF PROCESS
255 - 264.
The structure of the stable sub-nanoparticles, or clusters, containing 50 atoms or less, are reported for a range of geologically and industrially important ternary oxides, namely, (MgAl2O4)n, (Al2SiO5)n, (Mg2SiO4)n, and (MgSiO3)n. In general, there is a core-shell segregation of the cations, with the higher charged, smaller sized cations precipitated at the centre of each cluster, where their coordination to the anions can be maximized, whilst the lower charge cations are positioned in the outer layer. The smallest cluster where there is not a perfect core-shell segregation of the cations is found for Mg2SiO4, which interestingly has isolated SiO4 in its bulk phase. A Lamarckian-based evolutionary algorithm, using only phenotype moveclass operators, was employed to generate the global minimum structures. The Born model with pairwise interatomic potentials was adopted for the calculation of the cost function. For ternary oxides, interchanging cations can generate many isostructural configurations. Hence, the implementation of allowing new candidate structures (children) to be generated by simply swapping, at random, atoms within a current structure (parent) is investigated. The success rates of finding the target structures, as well as how the evolutionary algorithm (EA) scales with the number of atoms in the cluster, are reported.
|Title:||Structure Prediction of Ternary Oxide Sub-Nanoparticles|
|Keywords:||Genetic algorithms, Global optimization, Interatomic potentials, Nanoparticles, Semi-classical simulations, CRYSTAL-STRUCTURE PREDICTION, POWDER DIFFRACTION DATA, GENETIC ALGORITHM, EXCLUSION ZONES, EVOLUTIONARY ALGORITHMS, INTERATOMIC POTENTIALS, FRAMEWORK STRUCTURES, GLOBAL OPTIMIZATION, CLUSTERS, NANOCLUSTERS|
|UCL classification:||UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Chemistry|
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