Matthew H. Ford, Scott M. Auerbach and Peter A. Monson,
``On the Mechanical Properties and Phase Behavior of Silica:
A Simple Model Based on Low Coordination and Strong Association,''
J. Chem. Phys. 121, 8415-8422 (2004).
Abstract
We present a simple and computationally efficient classical atomistic model of silica in which the silicon
and oxygen are simulated as hard spheres with four and two association sites, respectively. We have performed isobaric-isothermal Monte
Carlo simulations to study the mechanical and phase behavior of this model. We
have investigated solid phase structures of the model corresponding to quartz, cristobalite, and coesite, as
well as some zeolite structures. For the model these phases are mechanically stable and highly incompressible. Ratios of zero-pressure bulk moduli and thermal expansion coefficients
for alpha-quartz, alpha-cristobalite, and coesite are in quite good
agreement with experimental values. The pressure-temperature phase diagram was
constructed and shows three solid phases corresponding to
cristobalite, quartz, and coesite, as well as a fluid or glass phase, behavior qualitatively similar to that seen for silica experimentally.
Prof SM Auerbach
2 November 2004