KDI: Multi-scale Simulation Including Chemical Reactivity in Materials Behavior Through Integrated Computational Hierarchies

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9980015BartlettThis is an award in the KDI initiative that is managed by DMR, CHE, and DMII. The objective of this proposal is to describe phenomena that are critically dependent upon chemistry in real materials. Such phenomena include subcritical crack propagation, fatigue in solids, chemical-mechanical polishing of semiconductors and optical components, and dislocation etchings. These effects occur because of the synergistic action of high strain and chemical reactivity on material surfaces. Simulation of such processes requires the development of a methodology that provides a reliable description of both chemical reactivity (including solvents and contaminants) and mechanical strain to fracture. These studies must be done on a large ensemble of particles while accounting for large departures of individual atoms from mechanical and chemical equilibrium. Quantum chemistry, surface electronic structure, and ensemble simulations of mechanics must be integrated simultaneously. An interdisciplinary team has been assembled to work on this problem. The project has three elements: (1) construct computational methods that integrate first-principles quantum mechanical calculations of electronic states of molecules and extended systems, large scale ensemble calculations for the dynamics of molecules and clusters, and dynamical calculations of highly strained macroscopic structures; (2) combine these mult-scale simulations of chemically sensitive materials with critical experimental data, and (3) develop and implement software technologies that manage information flow among assemblies of large, disparate computer programs without significant 'hands-on' manipulation. Developed computational tools will be applied to several prototypical systems: the brittle fracture of SiO2 exacerbated by the influence of solvents, chemical polishing of surfaces, and dislocations emitted in silicon. The central objective of coupling theoretical descriptions of chemical processes and mechanical processes that occur on larger length scales, will be carried out by a team that spans four universities, six departments, and two companies, centered at the Quantum Theory Project of the University of Florida. The team includes experts in all computational scales from the quantum mechanical scale to continuum descriptions. %%%This is an award in the KDI initiative that is managed by DMR, CHE, and DMII. The proposed work constitutes a new computational challenge. The PIs seek to couple different simulation methodologies, each able to describe chemical and mechanical processes, into a computational tool that will attack problems in which important chemical and mechanical processes occur concurrently. The developed simulation technique will be applied to the fracture failure in the presence of chemical solvents and to the chemical polishing of materials.***