Molecular dynamics of structural properties of molten CaO-SiO2 with varying composition

Molecular dynamics simulations of the xCaO-(1-x) SiO2 melts (x varying with the composition of melt) were performed to achieve some structural information. It is found that the first peak positions of Si-Si, Si-O and 0-0 partial radial distribution functions RDFs(3.165 Angstrom, 1.612 Angstrom and 2.6 Angstrom) agree very well with those of x-ray diffraction experiments. The discovered relation of coordinate number NSi-Si (r(0)) with the molar ratio of CaO is linear and the slope is -0.05617. The average bond lengths Of Si-O-b and Si-O-nb are 1.6275 similar to 1.630 Angstrom and 1.595 similar to 1.60 Angstrom, respectively. Both distribution curves of the angles O-Si-O and Si-O-Si show one peak. For the distribution of angle O-Si-O the positions of the peaks are just a little less than the typical tetrahedral angle 109.5degrees. And for angle Si-O-Si the positions of peaks fluctuate in the range from 148degrees to 151degrees. At last, the distribution of five Si-O tetrahedra was obtained and discussed.