3-BODY POTENTIAL MODELING OF UNDOPED AND ER3-DOPED LEAD SILICATE GLASS()

Molecular dynamics simulations (MD) using a three-body potential model was used to simulate the structure of undoped and Er3+-doped lead sil icate glass (PbO . SiO2). The structures of the doped and undoped glas ses v. ere analyzed and the results were compared to those found exper imentally using X-ray diffraction, nuclear magnetic resonance (NMR), a nd EXAFS. The simulations showed the presence of two networks. one in which silicate tetrahedra are present and the other in which lead-oxyg en polyhedra form a continuous secondary network. Simulations of the E r3+-doped lead silicate glass showed that the Er3+ ions are found in t he lend network. Erbium-erbium clustering was observed at concentratio ns greater than or equal to 2.0% Er3+. (C) 1997 Elsevier Science B.V.