Effect of Water on Dynamic Compression of Silica Glass and Melts Using Molecular Dynamics

Recent experiments have explored the high-pressure behavior of vitreous and liquid silica (SiO₂) to improve its equation of state for planetary sciences.  Specifically, it has been found that small amounts of water and hydroxide in hydrous silica glasses plays an important role in silica’s response to compression.  We investigate the effect of a range of water concentrations for hydrous glasses and compare the behavior to anhydrous glasses of comparable density.  We model silica with the ReaxFF potential which captures chemical bond breaking.  We compare computational Hugoniot response and wave speed with recent shock-ramp experiments conducted at Sandia National Labs for pressures of 20 to 80 GPa.  The atomistic scale simulations identify the mechanisms which most strongly influence dynamic response.

 

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.