Molecular dynamics investigation of structure and transport in the K₂O-2SiO₂ System using a partial charge based model potential

Abstract

Potassium disilicate glass and melt have been investigated by using a new partial charge based potential model in which nonbridging oxygens are differentiated from bridging oxygens by their charges. The model reproduces the structural data pertaining to the coordination polyhedra around potassium and the various bond angle distributions excellently. The dynamics of the glass bas been studied by using space and time correlation junctions. It is found that K ions migrate by a diffusive mechanism in the melt and by hops below tbe glass transition temperature. They are also found to migrate largely through nonbridging oxygen rich sites in the silicate matrix, thus providing support to the predictions of the modified random network model.