NERSC Initiative for Scientific Exploration (NISE) 2010 Awards

Thermodynamic, Transport, and Structural Analysis of Geosilicates Using the SIESTA First Principles Molecular Dynamics Software

Ben Martin, University of California, Santa Barbara

Associated NERSC Project: Large-Scale Molecular Dynamics of Geomaterials: The Glass Transition, Nanoscale Structure and Effects of Water on Molten Silicate Properties at High-Pressure, and Applications to Earth and Planets (m178), Principal Investigator: Frank Spera, University of California, Santa Barbara

This study will improve our understanding of how rocky planets form and how magmas in volcanoes can be studied theoretically, before they erupt into lavas on the Earth's surface.

First Principles Molecular Dynamics (FPMD) investigations of geoliquids at high temperatures and pressures has recently emerged as a valuable technique for studying the chemistry of materials present in the Earth's mantle where experimental results are sparse. FPMD is also useful for investigating the interaction between H2O and silicates because classical pair-potential Molecular Dynamics models using water are difficult to develop. Previous FPMD studies have used simulations of only ~100 atoms--far too few for a robust statistical analysis of the melt structure. SIESTA is a software package (available as a module on Franklin) that allows simulations of up to N~1000 atoms. We propose a full thermodynamics, transport, and structural study of silicates + H2O using SIESTA order-N technique that allows simulations with a relatively high number of atoms for comparison with other Molecular Dynamic and experimental studies.