Structural modelling of glasses using reverse Monte Carlo simulation

Abstract

ONE of the main difficulties in the study of glasses and other disordered materials is the production of structural models that agree quantitatively with diffraction data. In normal Monte Carlo simulation, an initial structure is allowed to rearrange in such a way that its energy is minimized. Reverse Monte Carlo simulation1 is a newly developed technique in which a structural model is adjusted so as to minimize instead the difference between the calculated diffraction pattern and that measured experimentally, so that good agreement is inevitable. No interatomic potential is required. Here we illustrate the potential of this method by fitting the structure of vitreous silica simultaneously to X-ray and neutron diffraction data. The result, a (mostly) continuous random network of corner-sharing SiO4 tetrahedra, is consistent with other models but, unlike them, is derived solely from the data.