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: Anh Ngo Applicant's institution: ANL Applicant's division: MSD Project Name: IntensitySim Project title: Simulation Support for APS Data with ab initio Hybrid Reverse Monte Carlo Associated funding: LDRD Other Systems: Science: Our high-level goal is to improve the methods for determining large-scale structure for materials imaged at the APS by using Hybrid Reverse Monte Carlo, a combination of DFT, energy, and X-ray intensity calculations. Project description: The Calculate_I software came out of the Discovery Engines LDRD for combining experimental science with simulation. The program is written in Fortran with MPI for parallelism. OpenMP integration is planned. The code is compute-intensive: it reads a small amount of data produced by experiment and writes out a ~1 MB atomic structure dataset at the end. The computational method used models and improves a simulated atomic struction. A Monte Carlo iteration process then proposes improvements. The potential improvements are evaluated based on an energy calculation and an X-ray scattering intensity comparison to experimental data. The programming model used is Fortran + MPI. The code has been tested on LCRC scales and is expected to scale beyond that. We think that the analysis of data recently produced at CHESS by Ray Osborn will produce a Nature Materials paper. This project will use our software, Calculate_I, supported by 2000 VASP calculations. The plan to run VASP 2000 times and Calculate_I once for each experimental data set. The project initially contains the developers: Anh Ngo and Justin Wozniak. We will perform structure optimizations based on APS experiments of mullite and NaXV2O5 with different magnetic configurations will be carried out using (2 x 1 x 2) bulk unit cells. By comparing different magnetic ordering energies we will conclude which configuration corresponding to the ground state energy. We will determine the ground state structure as a result of the density functional theory (DFT) calculations using the VASP package. Periodic boundary condition (PBC) will be imposed in order to maintain periodicity of the solid support. Gradient corrected PBE density functional will be used for these calculations. From there, we can run Calculate_I to optimize the large scale structure. Those programs are currently available on Blues cluster and scale reasonably well on parallel processors. Our total request is 200,000 core hours. Industry partnership: Project URL: Requested allocation: 300000 Q1: 0 Q2: 100000 Q3: 100000 Q4: 100000 Justification: Storage requirements: 100GB 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