The Yttria-Alumina Glasses - MD and TD Models

Abstract

The ab-initio molecular dynamics (MD) calculations of the yttrium - aluminate binary system 23Y2O3·77Al2O3 were performed with help of the Vienna ab-initio simulation package VASP. The thermodynamic model (TD) of glasses of the studied binary system was constructed. Both the Y/O and Al/O coordination numbers calculated from the partial pair radial distribution function (PP RDF) obtained for MD simulated melt at the temperature of 2500 K were significantly lower than the corresponding coordination numbers obtained from the TD model. The published neutron diffraction and X-ray diffraction studies give the results close to the results of the present ab-initio MD simulation. The TD model resulted in higher Al/O and Y/O coordination when compared with experimental results.

Calculation and analysis of vibrational spectra of PbCl2–Sb2O3–TeO2 glass from first principles

“…12.3% and 9.4%, respectively. The TeO 5 polyhedra are probably frozen intermediates of high temperature melting reactions [37][38][39] carried out under high pressure in this case. The large error-bars in Fig.…”

Molecular simulations of silicate melts doped with sulphur and nitrogen

“…Recently, the ab initio molecular dynamics has been used to study the structure and properties of many oxide glasses including silica [19], silicate [20][21][22][23] phosphosilicate [24], oxynitride [25,26], and aluminate glasses [27][28][29]. The chemical processes in the hydrous silica melt (3.84 wt.% H 2 O) at 3000 K and 3500 K [30] were simulated by the ab initio Car-Parrinello MD with 102 atoms, the PBE exchange-correlation functional, norm-conserving pseudopotentials, and plane-wave cut-off energy of 650 eV.…”