Search results for "Solid-state phase transformations"

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Negative pressures in CaWO4 nanocrystals

2009

Tetragonal scheelite-type CaWO4 nanocrystals recently prepared by a hydrothermal method show an enhancement of its structural symmetry with the decrease in nanocrystal size. The analysis of the volume dependence of the structural parameters in CaWO4 nanocrystals with the help of ab initio total-energy calculations shows that the enhancement of the symmetry in the scheelite-type nanocrystals is a consequence of the negative pressure exerted on the nanocrystals; i.e., the nanocrystals are under tension. Besides, the behavior of the structural parameters in CaWO4 nanocrystals for sizes below 10 nm suggests an onset of a scheelite-to-zircon phase transformation in good agreement with the predic…

Phase transitionMaterials scienceCalcium compoundsAb initioUNESCO::FÍSICAGeneral Physics and AstronomyNanoparticleNanostructured materialsCrystal symmetryCrystallographyTetragonal crystal systemNanocrystalAb initio quantum chemistry methodsChemical physicsTotal energy:FÍSICA [UNESCO]Phase (matter)Ab initio calculations ; Calcium compounds ; Crystal growth from solution ; Crystal symmetry ; Nanostructured materials ; Solid-state phase transformations ; Total energySolid-state phase transformationsAb initio calculationsCrystal growth from solutionMonoclinic crystal system
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