ITR/ASE-SIM: Multiscale Treatment of Systems with Strong Heterogeneities: Development of Hybrid Atomistic-Coarse-Grained Methodology and Computer Code

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Xiao Zeng, Dennis Diestler, and Ruqiang Feng of the University of Nebraska are supported by the Chemistry Division under the Information Technology Research program to develop a hybrid atomistic-coarse-grained computational methodology capable of describing multi-scale processes. Ruben Parra of DePaul University will also participate as a summer visiting scholar. The prototypical system consists of two planar solid substrates separated at the interface by a fluid film. In the vicinity of the interface, atoms can execute irregular, large-amplitude motions whereas far regions of the substrates are homogenously strained. The fluid and near regions are treated atomistically while the far regions are described by continuum mechanics as a coarse-grain mesh. Thermomechanical properties are computed at ensemble averages, which are effected by Monte Carlo simulation. The expected outcome of this research is a powerful computational technique for analyzing the thermomechanical response of realistic fluid-solid and solid-solid interfacial systems, in which the coupling of the molecularly heterogeneous interface to the macroscopic continuum plays as essential role. Although the specific formulations will be cast with the contexts of thin-film lubrication and nanoindentation, the approach is applicable to other real-world physical problems such as crack propagation.