Our long-term vision is for a comprehensive and fundamental understanding of a critical gas-surface reaction, nano-oxidation from the adsorption of oxygen atoms on the metal surface to the coalescence of the bulk oxide via coordinated multi-scale theoretical and in situ experimental efforts. Reaching this goal necessitates close collaborations between theorists and experimentalists, and the development and utilization of unique and substantial theoretical and experimental tools. Achievement of this goal will be a major breakthrough in dynamic surface/interface reactions that will dramatically impact several scientific fields. Many of these are of interest to DOE, such as thin films and nanostructures that use oxidation for processing, heteroepitaxy, oxidation and corrosion, environmental stability of nano-devices, catalysis, fuel cells and sensors. The purpose of this specific DOE program was the support for the theoretical effort. Our focus for the first round of funding has been the development of a Kinetic Monte Carlo (KMC) code to simulate the complexities of oxygen interactions with a metal surface. Our primary deliverable is a user-friendly, general and quite versatile KMC program, called Thin Film Oxidation (TFOx). TFOx-2D presently simulates the general behavior of irreversible 2-dimensional nucleation and growth of epitaxial islands on a square or rectangular lattice. The TFOx model explicitly considers a very large range of elementary steps, including deposition, adsorption, dissociation of gas molecules (such as O2), surface diffusion, aggregation, desorption and substrate-mediated indirect interactions between static adatoms. This capability allows for the description of the numerous physical processes involved in nucleation and growth. The large number of possible input parameters used in this program provides a rich environment for the simulation of epitaxial growth or oxidation of thin films. As a first demonstration of the power of TFOx-2D, the input parameters were systematically altered to observe how various physical processes impact morphologies. It was noted that potential gradients, developed to simulate medium-range substrate mediated interactions such as strain, and the probability of an adatom attaching to an island, have the largest effect on island morphologies. Nanorods, and round, square and dendritic shapes have all been observed (see section 2E) which correlate well with experimental observations of the wide range of oxide morphologies produced during in situ oxidation of Cu thin films. The people involved in the development and utilization of TFOx included a post-doc, Dr. Rich McAfee, and a graduate student, Ms. Xuetian Han. Both joined this program in August 2002. Dr. McAfee has been at Brashear Co., in Pittsburgh, PA since June 2004. To allow TFOx to be accessible to the rest of the scientific community, a web-site describing TFOx has been developed: www.tfox.org. No unexpended funds are expected at the completion of the current funding cycle. For in-depth development of the theoretical effort, the Principle Investigator (PI) proposed in the initial grant to collaborate with Dr. Maria Bartelt at Lawrence Livermore National Lab (LLNL). A graduate student, Dr. Guangwen Zhou, was supported within this DOE program for several months, where he was to collaborate with Dr. Bartelt. Unfortunately, Dr. Bartelt became very ill during this time and passed away in 2003. The focus of Dr. Zhou's thesis work (completed in December, 2003) was the wide variety of oxide nanostructures (e.g., nano-rods, domes, and pyramids) that form during oxidation of Cu thin films in situ. His primary contribution while supported on this DOE grant was the demonstration that the elastic strain relief model, as developed by Tersoff and Tromp to explain nanorod formation in Ge/Si system, explains Cu2O nano-rod formation when Cu(100) is oxidized around 600C. Validation of this model requires surface and interface energies, and ...

The purpose of this grant is to develop the multi-scale theoretical methods to describe the nanoscale oxidation of metal thin films, as the PI (Yang) extensive previous experience in the experimental elucidation of the initial stages of Cu oxidation by primarily in situ transmission electron microscopy methods. Through the use and development of computational tools at varying length (and time) scales, from atomistic quantum mechanical calculation, force field mesoscale simulations, to large scale Kinetic Monte Carlo (KMC) modeling, the fundamental underpinings of the initial stages of Cu oxidation have been elucidated. The development of computational modeling tools allows for accelerated materials discovery. The theoretical tools developed from this program impact a wide range of technologies that depend on surface reactions, including corrosion, catalysis, and nanomaterials fabrication.

Chemical sensors are integral to the automation of myriad industrial processes and everyday monitoring of such activities as public safety, engine performance, medical therapeutics, and many more. This 4 volume reference work covering simulation and modeling will serve as the perfect complement to Momentum Press's 6 volume reference works "Chemical Sensors: Fundamentals of Sensing Materials" and "Chemical Sensors: Comprehensive Sensor Technologies", which present detailed information related to materials, technologies, construction and application of various devices for chemical sensing. This 4 volume comprehensive reference work analyzes approaches used for computer simulation and modeling in various fields of chemical sensing and discusses various phenomena important for chemical sensing such as bulk and surface diffusion, adsorption, surface reactions, sintering, conductivity, mass transport, interphase interactions, etc. In this work it will be shown that theoretical modeling and simulation of the processes, being a basic for chemical sensors operation, could provide considerable progress in choosing both optimal materials and optimal configurations of sensing elements for using in chemical sensors. Each simulation and modeling volume in the present series reviews modeling principles and approaches peculiar to specific groups of materials and devices applied for chemical sensing. Volume 1: Microstructural Characterization and Modeling of Metal Oxides covers microstructural characterization of metal oxides using SEM, TEM, Raman spectroscopy and in-situ high temperature SEM, and multiscale atomistic simulation and modeling of metal oxides, including surface state, stability and metal oxide interactions with gas molecules, water and metals.

The aim of this book is to review innovative physical multiscale modeling methods which numerically simulate the structure and properties of electrochemical devices for energy storage and conversion. Written by world-class experts in the field, it revisits concepts, methodologies and approaches connecting ab initio with micro-, meso- and macro-scale modeling of components and cells. It also discusses the major scientific challenges of this field, such as that of lithium-ion batteries. This book demonstrates how fuel cells and batteries can be brought together to take advantage of well-established multi-scale physical modeling methodologies to advance research in this area. This book also highlights promising capabilities of such approaches for inexpensive virtual experimentation. In recent years, electrochemical systems such as polymer electrolyte membrane fuel cells, solid oxide fuel cells, water electrolyzers, lithium-ion batteries and supercapacitors have attracted much attention due to their potential for clean energy conversion and as storage devices. This has resulted in tremendous technological progress, such as the development of new electrolytes and new engineering designs of electrode structures. However, these technologies do not yet possess all the necessary characteristics, especially in terms of cost and durability, to compete within the most attractive markets. Physical multiscale modeling approaches bridge the gap between materials’ atomistic and structural properties and the macroscopic behavior of a device. They play a crucial role in optimizing the materials and operation in real-life conditions, thereby enabling enhanced cell performance and durability at a reduced cost. This book provides a valuable resource for researchers, engineers and students interested in physical modelling, numerical simulation, electrochemistry and theoretical chemistry.

Environmental protection and sustainability are major concerns in today’s world, and a reduction in CO2 emission and the implementation of clean energy are inevitable challenges for scientists and engineers today. The development of electrochemical devices, such as fuel cells, Li-ion batteries, and artificial photosynthesis, is vital for solving environmental problems. A practical device requires designing of materials and operational systems; however, a multidisciplinary subject covering microscopic physics and chemistry as well as macroscopic device properties is absent. In this situation, multiscale simulations play an important role. This book compiles and details cutting-edge research and development of atomistic, nanoscale, microscale, and macroscale computational modeling for various electrochemical devices, including hydrogen storage, Li-ion batteries, fuel cells, and artificial photocatalysis. The authors have been involved in the development of energy materials and devices for many years. In each chapter, after reviewing the calculation methods commonly used in the field, the authors focus on a specific computational approach that is applied to a realistic problem crucial for device improvement. They introduce the simulation technique not only as an analysis tool to explain experimental results but also as a design tool in the scale of interest. At the end of each chapter, a future perspective is added as a guide for the extension of research. Therefore, this book is suitable as a textbook or a reference on multiscale simulations and will appeal to anyone interested in learning practical simulations and applying them to problems in the development of frontier and futuristic electrochemical devices.

Multiscale Simulations and Mechanics of Biological Materials A compilation of recent developments in multiscale simulation and computational biomaterials written by leading specialists in the field Presenting the latest developments in multiscale mechanics and multiscale simulations, and offering a unique viewpoint on multiscale modelling of biological materials, this book outlines the latest developments in computational biological materials from atomistic and molecular scale simulation on DNA, proteins, and nano-particles, to meoscale soft matter modelling of cells, and to macroscale soft tissue and blood vessel, and bone simulations. Traditionally, computational biomaterials researchers come from biological chemistry and biomedical engineering, so this is probably the first edited book to present work from these talented computational mechanics researchers. The book has been written to honor Professor Wing Liu of Northwestern University, USA, who has made pioneering contributions in multiscale simulation and computational biomaterial in specific simulation of drag delivery at atomistic and molecular scale and computational cardiovascular fluid mechanics via immersed finite element method. Key features: Offers a unique interdisciplinary approach to multiscale biomaterial modelling aimed at both accessible introductory and advanced levels Presents a breadth of computational approaches for modelling biological materials across multiple length scales (molecular to whole-tissue scale), including solid and fluid based approaches A companion website for supplementary materials plus links to contributors’ websites (www.wiley.com/go/li/multiscale)