Structural properties of simulated amorphous GeO2 nanoparticles

Abstract

Structural properties of amorphous GeO2 nanoparticles have been studied by using molecular dynamics (MD) simulations. Four models with different sizes of 2, 3, 4 and 5 nm have been obtained by cooling from the melt via the MD method under nonperiodic boundary conditions. We used the interatomic potentials that have a weak Coulomb interaction and Morse-type short-range interaction. Structural properties of amorphous nanoparticles obtained at 300 K have been analyzed in detail through the partial radial distribution functions (PRDFs), mean interatomic distances, coordination number and bond-angle distributions compared with those observed for the bulk counterpart. Moreover, the radial density profile in nanoparticles was found and discussed. Calculations showed that size effects on structure of amorphous GeO2 nanoparticles are significant in that if the size is larger than 3 nm amorphous GeO2 nanoparticle has a distorted tetrahedral network structure with the mean coordination number ZGe-O ≈ 4.0 and ZO-Ge ≈ 2.0 like those observed in the bulk counterpart. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.