Hello, A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: John Russell Applicant's institution: ANL Applicant's division: MSD Project Name: lith_ox_md Project title: Molecular Dynamics Calculations of Lithium Oxides Associated funding: Strategic LDRD project entitled Multiscale Modeling of Advanced Electrical Energy Storage Systems Other Systems: Carbon, CNM Science: We will perform molecular dynamics (MD) simulations on nanocrystalline lithium-oxide compounds (including Li2O and Li2O2) of relevance to lithium-air batteries. These simulations include determination of the structures, energies and some properties (such as the diffusivities) of the free surfaces and grain boundaries in these microstructures. A key feature of the simulation approach involves the use of a method to evaluate the Coulomb energy, forces and stresses by direct 1/r summation with spherical truncation (Wolf et al. 1999). This order-N method, which has recently been incorporated into the LAMMPS code that will be used for this work, is computationally superior to both the widely used Ewald method and fast-multipole methods while at the same time producing numerically identical and physically more transparent results. Using this approach, we are able to consider ionic systems consisting of a very large number of ions, thus enabling elucidation of microstructural phenomena and physical behavior that can subsequently be used as input to parameterize a physically realistic mesoscale battery model of microstructure evolution during the charge/discharge cycle. Project description: The goal of this project is calculate structural and thermodynamic properties of lithium-oxide materials and to develop parameters for collaborators studying mesoscale models where experimental values may be unavailable. Our approach will be to use a Buckingham potential to model covalent interactions and a Wolf summation potential for elecrostatic interactions in a fixed charge Li2O model as implemented in the LAMMPS molecular dynamics package. Our model systems will include free particles, surfaces and nanocrystalline materials. This modeling approach is well suited for large systems due to the favorable scaling of the potentials and software. LAMMPS is massively parallel with nearly linear scaling with system size which can allow for 100k+ atom models for tens of nanoseconds. Project URL: Requested allocation: 900000 Q1: 225000 Q2: 225000 Q3: 225000 Q4: 225000 Justification: Both the Buckingham potential and the Wolf summation method scale as pair potentials. LAMMPS benchmarks are available for 1-billion atom LJ models and also scaling for LJ systems with up to 64k processors. http://lammps.sandia.gov/bench.html The requester has used undetermined amount hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System