Iron surrounding in CaO-FeO-2SiO2 glass: EXAFS and molecular dynamics simulation

Abstract

EXAFS interpretation of iron-bearing glasses has been controversial. In order to get new information, the surrounding of iron in a synthetic Fe2+-bearing glass (CaO-FeO-2SiO2) has been investigated by combined use of EXAFS spectroscopy and Molecular Dynamics (MD) simulation. The radial distribution functions of oxygen atoms around Fe are compared. While MD simulation reveals the existence of 4-fold and 5-fold coordinated iron, EXAFS evidences a short Fe-O distance, classically attributed to 4-fold coordinated iron. An explanation for this apparent discrepancy is proposed.