September 2014 - Allocations-admins - mailman3.cels.anl.gov

[LCRC Accounts] Project Request: FF-IrO
by accounts＠lcrc.anl.gov 11 Sep '14

11 Sep '14

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: Fatih Sen Applicant's institution: ANL Applicant's division: NST Project Name: FF-IrO Project title: Force field development for Ir-O system Associated funding: LDRD (Materials for Energy Strategic Initiative) Other Systems: CNM Carbon (680,000 hours) Science: Iridium oxide (IrOx) nanoclusters are promising candidates as water splitting catalysts for the efficient solar energy into fuel (H2) conversion process. The size, shape and structure of nanoclusters drastically affect the catalytic performance of IrOx. However, due to experimental limitations at the nano-scale, and the absence of an atomic scale empirical force field; a systematic investigation of IrOx nanoclusters at various sizes has not been reported. This study aims to develop a force field for the Ir-O system that is tailored to predict the structural properties of IrOx nanoclusters and bulk properties of iridium oxides accurately. The existing Morse + QEq force field was reported to accurately mimic the ionic and covalent bonds in metal oxides and is suitable to predict IrOx structural and thermodynamic properties. We will parameterize the Morse + QEq for the Ir-O system, and also use the same dataset to parameterize a reactive force field, Re axFF to investigate the oxidation process of Ir and mechanisms of the formation of IrOx nanoclusters. The developed force field will enable elucidation of mechanisms that morphological and structural properties of nanoclusters play on their catalytic efficiency towards development of more robust solar fuel production processes. Project description: Molecular dynamics simulations based on empirical force fields can predict many important structural and chemical properties that are not easily obtained through experimentation. In this project, we propose to develop a reactive force field for Ir-O system that can predict the formation, stability and reactivity of IrOx nanoclusters. The study begins with density functional theory (DFT) calculations for various Ir and Ir oxide structures of different sizes, strains, phases, surfaces and shapes at the nano and bulk scale to generate an extensive training set for the force field fitting process. Using these training structures, evolutionary algorithms will be employed to parameterize the Morse + Qeq and ReaxFF force fields. Finally, the developed force field will be used to estimate the structural and physical properties of the IrOx nanoclusters compared to experimental findings related to water splitting reaction. The generation of training set for the parameterization of the force field will be carried out by calculating the total energies and forces of various systems using the plane wave code Vienna ab initio simulation package (VASP), which is already available in LCRC systems. The PBE exchange correlation and projector augmented wave (PAW) method will be used. All calculations will be carried out considering the spin polarization, spin orbit coupling and Hubbard U parameter, which will demand 3 times more computation time than without these options. A large training data set is required to obtain an accurate fitting for complex functional forms such as ReaxFF with many parameters so that the data set will include the following calculations: i) Bulk structural and mechanical properties for experimental and hypothetical crystal structures of Ir (fcc, bcc, hcp) and IrO2 (rutile, pyrite, anatase, brookite, columbite) will be carried out. These calculations are estimated to take 10,000 core hours. ii) Surface calculations for both Ir and IrO2 include 10 different surface orientations for which at least 5 different slab thicknesses will be considered. Each of these calculations is expected to take in average 30 hours of simulation time in 32 cores. Total simulation time is expected to be 30 * 32 * 5 * 10 = 48,000 core hours. iii) Nanoclusters of Ir and IrOx with four different sizes (5 – 10 Ir atoms) will be generated. For each nanocluster size, total energies of approximately 500 configurations will be calculated, starting with a random sample and evolving into the global minimum using genetic algorithm. One such calculation is estimated to take 12 hours in 16 cores. Total required time is 16 * 12 * 500 * 4 = 384,000 core hours. iv) The parameterization of the force field will be accomplished using our current serial genetic algorithm. However, a parallel genetic algorithm code will be developed and utilized in the project at later stages. The fitting process is estimated to take 20,000 core hours. v) Finally, MD simulations will be carried out to evaluate the stability and structural properties of iridium oxide nanoclusters using the developed force field. The time estimated for each simulation to be 10 hours in 16 cores. Total 100 MD simulations are estimated to require: 10 *16 * 100 = 16,000 core hours. Industry partnership: N/A Project URL: Requested allocation: 478000 Q1: 119500 Q2: 119500 Q3: 119500 Q4: 119500 Justification: N/A Storage requirements: 1 TB 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

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[LCRC Accounts] Project Request: AuFF
by accounts＠lcrc.anl.gov 11 Sep '14

11 Sep '14

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: Badri Narayanan Applicant's institution: ANL Applicant's division: NST Project Name: AuFF Project title: Development of classical bond-order force field for gold nanoclusters from first principles Associated funding: LDRD (Materials for Energy Strategic Initiative) Other Systems: Carbon cluster at the Center for Nanoscale Materials; 600,000 core hours Science: Gold nano-clusters, owing to their exceptional chemical, optical, and electronic properties, hold promise in a wide range of applications, such as optoelectronics, bio-recognition, and catalysis [1]. Their enticing potential has fueled numerous theoretical and experimental investigations; however, a fundamental understanding of surface chemistry and atomic structure of Au nano-clusters is still elusive [2]. For instance, there is an open debate on the critical value of cluster size n (i.e., number of atoms) beyond which 3D isomers become energetically preferable over planar ones, with reported values ranging from 7 to 15 [2-4]. Furthermore, since many isomers at a given cluster size are energetically close to each other (~20 meV/atom) [4], it is possible that they may undergo structural transitions under the influence of external stimuli, e.g., temperature fluctuations; the knowledge of such transitions and the associated mechanisms is still in its i nfancy. Global optimization and molecular dynamics (MD) simulations based on classical potentials provide an ideal route to address these issues; however, the accuracy of these methods is severely limited by the force fields (FFs) currently available in the literature. To improve the predictive power of these available potentials, our group re-parameterized existing force fields with pre-defined functional forms by training them against thermodynamic and structural properties obtained from density functional theory (DFT) calculations. The training set was well represented by structures (clusters and bulk) that are near- and far- away from equilibrium. This work indicated that functional forms for pair wise potentials (e.g. Morse) and those that account for many body effects via a density term (e.g., Sutton-Chen) do not possess sufficient complexity to describe the whole range of structures exhibited by Au clusters such as planar, hollow cages/tubes, globular, space-filled icosahedral configurations. FFs based on bond-order formalism, e.g., Tersoff, are more likely to be capable of describing such a wide range of structures; for instance, in the case of carbon, Tersoff FF can describe graphene, nanotubes, graphite, as well as diamond [5]. Here, a FF for gold based on bond-order formalism will be developed using structural and thermodynamic properties obtained from DFT calculations. The initial efforts will be focused on a Tersoff type potential coupled with long-range attractive potentials (e.g. Lennard –Jones); we will also explore potentials with flexible functional forms determined using sparse regression techniques. To ensure robustness and accuracy of the FF, we will employ an extensive training set comprising of DFT calculated energies of numerous condensed phases, nano-clusters at various sizes, and low-/high- index surfaces. In addition, we will obtain metastable structures of Au nanoclusters at low sizes (n < 15) using evolutionary optimization techniques. Once the FF is developed for Au nano-clusters, it would (a) enable a fundamental understanding of structure of Au nano-clusters, (b) unravel the atomic-scale dynamical processes that underpin catalysis and other interesting phenomena (e.g., structural transitions) via MD simulations, as well as (c) establish a novel methodology for developing force fields that can be easily extended to other relevant systems (e.g., Li-Si). In a broader context, the development of such a generic methodology for robust force-field generation is imperative to supply necessary computational tools to access the length and time scales necessary for studying atomic-scale processes at reactive interfaces. Such a fundamental understanding is urgently required to make truly pathbreaking advances in the design of functional materials at the nano-scale for energy applications. [1] P. Pyykkö, “Theoretical chemistry of gold”, Angewandte Chemie 43, 4412 (2004). [2] S. Bulusu et al., “Evidence of hollow golden cages”, Proceedings of the National Academy of Sciences of the United States of America 103, 8326 (2006). [3] P. Gruene et al. "Structure of neutral Au7, Au19 and Au20 clusters in the gas phase" Science 321, 674 (5889). [4] X. Li, et al., “Structural study of gold clusters”, Journal of Chemical Physics 124, 114309 (2006). [5] L. Lindsay and D. Baido, “Optimized Tersoff and Brenner empirical potential parameters for lattice dynamics and phonon thermal transport in carbon nanotubes and graphene”, Physical Review B 81, 205441 (2010). Project description: For generating the training dataset of total energies and forces, we will employ the plane-wave DFT package VASP using the relativistic Perdew-Burke-Erzenhoff pseudopotentials in the framework of generalized gradient approximation. Our group is well experienced in these calculations in Fusion where the code has been tested for systems having up to 7000 electrons. For routine calculations, the code showed 70%-80% scaling efficiency for 64 to 128 cores compared to 8 cores. Given this performance, the VASP code has the efficiency to simulate large number configurations in reasonable amount of time. The calculations with classical FF will be performed using LAMMPS, which is well known to be a massively parallel molecular dynamics package, which scales excellently and has been routinely used for computational supercells containing unto million atoms. The proposed calculations along with their estimated compute time requirements are listed below: 1. Evolutionary algorithm based search for metastable clusters (planar and globular configurations) in the framework of DFT (PAW-PBE) at 2 different cluster sizes (n =12,14). Our preliminary calculations for the 13 atom cluster has shown such a search at each cluster size requires DFT relaxations of reasonable quality on ~300 random structures (~6 hours on 16 cores per DFT relaxation). So for three cluster sizes, we expect to need 2 cluster sizes * 2 (globular, planar) * 300 * 16 * 6 = 115,200 core hours. 2. At each of these cluster sizes (n = 12,14), we will perform high quality electronic structure calculations using DFT for 10 best structures to identify the electronic origins of energy differences between isomers that have identical number of dangling bonds. Such a calculation would require ~8 hours on 32 cores; so we need 2 * 10 * 8 * 32 = 5120 core hours. 3. For the fitting procedure, we would require ~1000 core hours per FF. We will fit (a) two existing bond order potentials (Tersoff, ReaxFF), (b) Tersoff potential coupled with long range attractive Lennard-Jones potential, and (c) a new reactive FF, wherein the potential is described as a linear superposition of various basis set functions. So we need 4 * 1000 = 4,000 core hours. 4. Gold nano-clusters have been found to exhibit interesting configurations, e.g., tubular Au24 and chiral Au34. To investigate whether such configurations possess exotic electronic, optical or magnetic properties, we will select 5 best structures at each size and perform high quality electronic structure calculations on them. Each of these calculations would require ~12 hours on 32 cores; so we need 45 * 10 * 6 * 32 = 172,800 core hours. 5. Finally, we will identify the atomistic origin of the shift in energetic preference from planar to globular isomers around cluster size of 13 atoms via MD simulations. Our preliminary computations have shown that a MD run of 50 ns needs ~1000 core hours. To explore the 2D-3D transition, we will study the trajectory of an ad-atom on planar Au13 cluster via MD simulations; 5 different candidate configurations for planar Au13 will be used and the simulations will be carried at 10 different temperatures; so we need 5 * 10 * 1000 = 50,000 core hours. The total time requested for this project is 350,000 core hours Dr. Badri Narayanan, Dr. Subramanian Sankaranarayanan, and Dr. Maria Chan will be responsible for carrying out the simulations. Industry partnership: Project URL: Requested allocation: 350000 Q1: 87500 Q2: 87500 Q3: 87500 Q4: 87500 Justification: Storage requirements: 1 TB 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

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[LCRC Accounts] Project Request: VO2_conductivity
by accounts＠lcrc.anl.gov 11 Sep '14

11 Sep '14

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: Alper Kinaci Applicant's institution: ANL Applicant's division: NST Project Name: VO2_conductivity Project title: First principles studies of electronic transport properties in Vanadium Dioxide Associated funding: This work is funded by a work-for-other proposal sponsored by the Toyota Motor Engineering & Manufacturing North America (TEMA). Other Systems: Carbon cluster at the Center for Nanoscale Materials, rapid access proposal pending. Science: Metal to insulator transition (MIT) is an intriguing phenomenon that may be facilitated by electron localization, carrier doping and electron-phonon coupling. The localization effects can be introduced via disorder (Anderson transition) [1] imposing a strong random potential or strong Coulomb (Mott–Hubbard transition) [2] repulsion between electrons. Electron-phonon coupling (Peierls transition) [3] also contributes to the opening of a band gap by periodic lattice distortion. Since in many systems, the MIT is accompanied by phase transformation, the primary cause of the change in conductivity (i.e. Mott–Hubbard or Peierls) is elusive [4]. Vanadium dioxide, VO2, is one of the appealing materials due to its near room temperature (T-MIT=340 K) transformation from monoclinic insulating phase to metallic rutile phase as temperature is increased [5]. Above the transition temperature, the electronic conductivity dramatically increases by several orders of magnitude [6]. According Wiedemann-Franz law, the MIT also affects the electronic contribution to the thermal conductivity. As a consequence, the electronic thermal conductivity of VO2 also increases when the temperature reaches the transformation temperature. Thus, near room temperature switching is possible for not only electronic but also thermal conductivity. These properties open many opportunities for device applications by tuning various ambient parameters. The switching can be induced by electric field [7-9], photons [10, 11] and pressure [12]. The structural transformation of vanadium dioxide also results in significant changes in its optical properties which can be manipulated to produce thermochromic windows [13] around ambient temperature. By using different dopants and alloying elements, it is possible to manipulate MIT phenomena in strongly correlated systems. Suppression of transition, changing T-MIT, phase separation and structural modification are some outcomes of doping and alloying [14-17]. In this project, we will analyze the effect of alloying/doping elements on the structure and the conductivity of VO2 in both conductive and insulating phases. For this purpose, density functional theory (DFT) calculations along with Boltzmann transport equation (BTE) will be employed. To model these strongly correlated systems, performance of DFT calculations with different exchange-correlation functionals will be tested. [1] P. W. Anderson, Phys. Rev. 109, 1492 (1958). [2] N. F. Mott, “Metal-Insulator Transitions” (Taylor and Francis, London 1990). [3] G. Gruner, Rev. Mod. Phys. 60 1129 (1988). [4] A. Perucchi, L. Baldassarre, P. Postorino and S. Lupi, J. Phys.: Condens. Matter 21, 323202 (2009). [5] R. M. Wentzcovitch, W. W. Schulz and P. B. Allen, Phys. Rev. Lett. 72, 3389 (1994). [6] F. J. Morin, Phys. Rev. Lett. 3, 34 (1959). [7] D. Ruzmetov, G. Gopalakrishnan, C. Ko, V. Narayanamurti, and S. Ramanathan, J. Appl. Phys. 107, 114516 (2010). [8] H.-T. Kim, B.-G. Chae, D.-H. Youn, G. Kim, K.-Y. Kang, S.-J. Lee, K. Kim, and Y.-S. Lim, Appl. Phys. Lett. 86 242101 (2005). [9] Nakano, M., Shibuya, K., Okuyama, D., Hatano, T., Ono, S., Kawasaki, M., Iwasa, Y. & Tokura, Nature 487, 459 (2012). [10] M. Nakajima, N. Takubo, Z. Hiroi, Y. Ueda, and T. Suemoto, Appl. Phys. Lett. 92, 011907 (2008). [11] A. Cavalleri, Th. Dekorsy, H. H. W. Chong, J. C. Kieffer, and R. W. Schoenlein, Phys. Rev. B 70, 161102(R) (2004). [12] E. Arcangeletti, L. Baldassarre, D. Di Castro, S. Lupi, L. Malavasi, C. Marini, A. Perucchi, and P. Postorino, Phys. Rev. Lett. 98, 196406 (2007). [13] H. Kakiuchida, P. Jin, M. Tazawa, Sol. Energ. Mat. Sol. C. 92, 1279 (2008). [14] C. Marini, E. Arcangeletti, D. Di Castro, L. Baldassare, A. Perucchi, S. Lupi, L. Malavasi, L. Boeri, E. Pomjakushina, K. Conder, and P. Postorino, Phys. Rev. B 77, 235111 (2008). [15] K. Shibuya, M. Kawasaki, and Y. Tokura, Phys. Rev. B 82, 205118 (2010). [16] K. W. Kim, J. S. Lee, and T. W. Noh, S. R. Lee and K. Char, Phys. Rev. B 71, 125104 (2005). [17] R. Shabna, P. M. Sarun, S. Vinu, A. Biju and U. Syamaprasad, Supercond. Sci. Technol. 22, 045016 (2009). Project description: Density functional theory calculations will be performed using the plane wave code VASP. Boltzmann transport equation calculations will be performed with the BoltzTraP code. (1) We will test DFT with semilocal, and hybrid functionals, as well as DFT+U method for VO2. A direct or indirect comparison with the experimental data is necessary to choose the most appropriate method for the next step. Since there is indication that the density of states (DOS) at the Fermi level for the metallic state near a MIT is related to the conductivity, we will investigate the validity of using the DOS as a proxy for electronic conductivity. (2) With the appropriate calculation method available, the next step is to model the electronic conductivity of MIT material with dopants. Different dopants can differ significantly in the following properties: a. Vary the electrical conductivity compared to the parent material. b. Solubility in the parent material. c. Induce structural changes after doping. Initially 5 different transition metals (Ti, Cr, Zr, Nb, Mo) will be evaluated for their solubility and substitutional defect formation energies. Thermodynamic analysis will be carried out to ensure phase stability of the doped compound. The deformation of the lattice will also be inspected. To study smaller dopant concentrations, 2x2x2 or 3x3x3 supercells will be used. (3) To further corroborate the results, BTE calculations will be performed using experimental relaxation times to estimate the electrical conductivity in pristine structure evaluated with different methods. The electronic transport in doped structures will also be investigated using BTE. The DFT calculations will be performed using the plane wave DFT code VASP. The code is tested in Blues with a 350 electron system and 65%-80% scaling efficiency is obtained 64 to 128 cores compared to 16 cores. In Fusion where the code has been tested for systems having up to 7000 electrons, the code showed 70%-80% scaling efficiency for 64 to 128 cores compared to 8 cores. Given this performance, the VASP code has the efficiency to simulate large number configurations in reasonable amount of time. Based on the previous experience on Fusion, the time estimates for each item are listed below. BoltzTraP is a serial code and only 1 core will be used for each calculation. The total time required for the 1 core simulations are estimated to be 2.5% of all requested time. The time estimates for the various parts above, based on benchmark results with VASP, are listed below. 1) Testing different functionals and U parameters on VO2: 100,000 core hours (include testing of various convergence parameters) 2) Doping studies: 250,000 core hours (5 TM species * 4 compositions * 10 atomic configurations * 1250 core-hours) 3) Boltzmann transport calculations: a- 40,000 core hours (increased k-point density for Boltzmann transport calculations). b- 10,000 core hours (BoltzTraP calculations). The total requested time is 400,000 core-hours. Dr. Alper Kinaci and Dr. Maria Chan will be responsible for carrying out the simulations. Industry partnership: The project is funded by TEMA and is part of an ongoing partnership between Argonne and Toyota in the experimental and computational investigations of novel ways to control thermal transport. Project URL: Requested allocation: 400000 Q1: 100000 Q2: 150000 Q3: 100000 Q4: 50000 Justification: Storage requirements: 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

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[LCRC Accounts] Yearly Allocation Request for HEIGHTS-3D
by accounts＠lcrc.anl.gov 11 Sep '14

11 Sep '14

Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Tatyana Sizyuk Project Name: HEIGHTS-3D Division: NE Project title: Advanced 2D and 3D Laser-Produced Plasma Processes modeling for EUV and BEUV Lithography and other advanced plasma applications. Modeling of plasma material interaction during edge-localized modes and disruptions in fusion devices. Associated funding: NSF, PIRE grant Other Systems: Science: Predictive analysis and optimization of plasma devices, such as laser produced plasma (LPP), discharge produced plasma (DPP), of fusion reactor environment, require accurate description of all possible processes occurring during photon/particles/target interactions. Models and methods should be carefully tested, revised and benchmarked to make realistic predictions without any assumptions or adjustment parameters. The HEIGHTS package from this point of view is being continuously upgraded and benchmarked for various energy sources and for different materials. This is the main point of our research and analysis. This leads to the development of comprehensive models integrated in a self-consistent manner to describe realistic conditions and to optimize plasma devices. HEIGHTS package is being developed as a comprehensive tool for simulation and optimization of various interaction processes during intense power deposition of various energy sources such as plasma, laser, and particle beams incident on target materials. This is multi-physics multi-phase package that combines state-of-the art models of energy deposition, vapor/plasma formation/evolution and magneto hydrodynamic (MHD) processes, thermal conduction in material and in plasma, atomic physics and resulting opacities, detailed photon radiation transport, and interaction between plasma/radiation and target material in full three dimension configurations. Project description: We use splitting methods that involve decoupling the full model into separate components for each process, employing specialized numerical methods to solve each component, and coupling the resulting solutions. Modeling of the entire evolution of laser produced plasma (LPP) in HEIGHTS package utilizes the most suited numerical and physical models for LPP plasma, e.g., weighted Monte Carlo methods for laser deposition and plasma radiation, phase change and thermal vaporization based on surface atoms kinetics modeling, Eulerian/Lagrangian description of plasma hydrodynamic evolution in multidimensional finite volume approximation, and implicit methods for plasma thermal conduction and magnetic diffusion with sparse linear equations solvers. Plasma thermodynamic properties and optical coefficients are calculated using the self-consistent Hartree-Fock-Slater (HFS) model implemented in HEIGHTS. The populations of atomic levels, ionization balance, and the ion and electron plasma concentrations are obtained based on the collisional-radiative equilibrium (CRE) approximation. Tabulated plasma properties and optical coefficients for wide range of temperatures and densities are used during the simulation of whole cycle of plasma evolution in LPP. Above models in the frame of HEIGHTS package will be used for the simulation and optimization of various plasma physics applications. These models will be extended to describe plasma evolution in femtosecond laser devices where intense laser beams irradiate materials creating warm dense matter with specific characteristics. HEIGHTS package is being updated on continuing basis with frequent add-on of new modules, improving of developed physical models and mathematics, and revising of parallel computing methods. We will study the following state-of-the art multi-phase multi-physics applications: 1. Laser produced plasma evolution in presence of ambient gas to predict material erosion, plume propagation and emission. 2. Analysis of plasma phenomena produced by intense femtosecond lasers. 3. Optimization of LPP devices for EUV and BEUV lithography using both YAG and CO2 lasers, pre-pulse/main pulse, mass-limited tin targets. 4. Analysis and prediction of colliding plasmas physics for various applications. We would like to request 450,000 allocation hours to conduct various optimizations, benchmarking, and parametric studies of the HEIGHTS 3D packages for several projects during FY2015. ~30% of the allocation will be for non-parallel jobs Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 450000 Q1: 110000 Q2: 120000 Q3: 110000 Q4: 110000 Justification: Storage requirements: Thank You, The LCRC Accounts System

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[LCRC Accounts] Project Request: Li-S_Sol
by accounts＠lcrc.anl.gov 11 Sep '14

11 Sep '14

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: Kah Chun Lau Applicant's institution: ANL Applicant's division: MSD Project Name: Li-S_Sol Project title: Li-S battery Solution Associated funding: DOE BES-JCESR Other Systems: Science: Over the past two decades, the application of Li-ion batteries have proven to be very successful in the consumer portable electronics and will continue to play a significant role in other scale of energy storage devices (e.g. automobile, stationary energy storage, etc.) in the near future. With the ultimate goal to increase the energy density, a lot of research and developments activities are currently actively pursuing alternative Li-based cathode materials such as oxygen and sulfur that can potentially offer greater capacities that exceed those conventional Li-insertion cathodes (e.g. LiMn2O4). As a result, a systematic study on Lithium-sulfur (Li-S) batteries that have a theoretical capacity as high as ~ 2600 mAh/g is definitely important. In contrast to Li-insertion or Li-intercalated cathode materials, the thermodynamically huge energy is released when sulfur is undergoing a series of compositional, structural and morphological changes during discharge/charge cycling, which involve soluble polysulfides and insoluble sulfides from the active materials. As a result, a detailed understanding of the complex reaction, ions dynamics and the evolution changes of electrochemical interfaces are necessary to account for future commercialization of this new technology. In this proposal, we shall only focus on two problems, i.e. (I) solubility prediction of polysulfides, and (II) ion diffusion of soluble polysulfides in bulk electrolytes. To date, the degree of solubility of the polysulfides (Li2S, Li2S2, and Li2Sn, n > 2) species in various electrolytes that can dramatically affect electrochemical behaviors of Li-S batteries remains elusive. Based on current studies [1], it has been found that the chain-ether [e.g. DME, TEGDME, etc.] based electrolytes have a better solubility for lithium polysulfides (Li2Sn, 4 ≤ n ≤ 8) but increase the viscosity of these electrolytes, and therefore becoming less conductive which is crucial for charge transfer. In order to have a systematic study at the fundamental level, a combined DFT, quantum thermochemistry and Ab Initio Molecular Dynamics (AIMD) atomistic simulation will be used to provide a reasonable model and prediction to this problem. From this approach, free energies of solution and solvation that needed to predict molecular solubility of polysulfides and sulfides will be obtained through the high-level quantum chemistry method. To account for the realist ic bulk electrolyte environment, the reasonable configuration of various solvated polysulfides species will be obtained using AIMD simulation. Based on the proposed problem (item #1) in previous paragraph, various thermodynamic samples of several solvated polysulfides and sulfides species within a bulk electrolyte at ambient temperature will be obtained (item #2). As a result, detailed studies of chemical conformation, ionic diffusion, dynamic charge transfer, phonon frequencies, etc. at ambient condition for different electrolytes will be analyzed based on AIMD simulations. Subsequently, these theoretical prediction and findings will be validated by PI’s experimental colleagues at ANL, MIT and Sandia National Lab through the collaboration funded by DOE BES-JCESR. Project description: The project can be divided into two related problems: (I) Solubility of polysulfides and sulfides A systematic quantum thermochemistry calculation of free energy of solvation for lithium polysulfides (Li2S, Li2S2, and Li2Sn, n > 2) will be carried out using Gaussian09 code. For each polysulfides species, the effect of a range of solvent dielectric constant will be investigated systematically. This will give a set of various optimized configurations of solvated polysulfides as an input for initial configuration in AIMD bulk simulation using VASP code. (2) Dynamics of solvated polysulfides species >From the item#1, at least two different bulk solvent electrolytes will be chosen for AIMD NVT simulation to investigate the dynamic properties (e.g. ion diffusion) of the solvated polysulfides species. Overall, the calculations will be carried out either based on VASP or CP2K. Calculation size For a standard quantum thermochemistry calculations (item#1), we plan to simulate about at least about 20-30 configurations for the low energy configurations of polysulfides. To obtain a reasonable good accuracy with high level quantum chemistry calculations, about 100 K processor hrs is needed. The smallest cells for which the effects of interest can realistically be simulated for electrolyte AIMD simulation will contain about four hundred atoms. All numerical shortcuts (gamma-point only, soft pseudopotentials) will be exploited. We expect to run on 256 processors. Of the calculations proposed here, the AIMD simulations (item 1 and 2) will have the largest CPU-time requirements per unit MD-time step of 1 fs. The AIMD simulations performed in NVT-ensemble simulations may require about 1 processor-hr per time step, for a cell size of about 400 atoms (using perhaps 256 processors). Obtaining a reasonably good MD statistics calculation may require of the order of 100 k processor hrs. In our problem, at least two to three different electrolytes will be explored, therefore it requires 500k processor hours for AIMD simulation for both item#1 and #2. Thus requirements for the entire project are thought to be 600,000 processor hours. Industry partnership: Project URL: Requested allocation: 600000 Q1: 150000 Q2: 150000 Q3: 150000 Q4: 150000 Justification: The smallest cells for which the effects of interest can realistically be simulated will contain about three to four hundred atoms electrolyte. All numerical shortcuts (gamma-point only, soft pseudopotentials) will be exploited. We expect to run on about 256 processors, a parallel efficiency of ~ 60% -75% can be achieved using 256 cores for VASP AIMD simulation. Thus to explore a moderately large systems (~ 300-400 atoms) with simulation time up to ~ 5ps in 1 fs time step, about 100 000 core-hour is sufficient to obtain to reasonably good thermodynamic statistics. Storage requirements: 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

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[LCRC Accounts] Project Request: QM_Storage
by accounts＠lcrc.anl.gov 11 Sep '14

11 Sep '14

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: Rajeev Surendran Assary Applicant's institution: ANL Applicant's division: MSD Project Name: QM_Storage Project title: Organic Materials for Energy Storage Associated funding: BES: JCESR Other Systems: CNM Science: Understanding, controlling, and eventually manipulating functional groups on promising organic molecules can be used to obtain the wide electrochemical window needed for the next generation of non-aqueous redox flow battery electrolytes. Combined electrochemical measurements in combination with accurate quantum calculations to probe structure-activity relationships of redox active molecular (RAM) species and to study their interactions with the surrounding electrolyte with an overall goal of developing key descriptors for predicting performance and stability of various organic compounds is central to this project. Predictive quantum chemical simulations based on density functional theory is utilized to compliment electrochemical experiments to investigate the redox properties of redox active organic molecules. The project is an integral part of the Materials Discovery associated with the Non-aqueous redox flow thrust of Joint Center of Electrical Ene rgy Storage (JCESR) at the Argonne National Laboratory. Project description: Project Description Electronic-structure based calculations have been extensively used to investigate the electronic structure of redox couples, while their application for explaining the electrochemical processes in redox flow batteries has been largely unexplored. Using the density functional theory framework, we will address a priori understanding of important electrochemical studies such as the following, as shown in Scheme 1. 1) Redox windows 2) Substitutent effects on improving the redox windows 3) Detailed computations to explore the side reactions 4) Assess the stability of cations/anions 5) Reactivity of molecules/ions at the electrode interphase. For organic materials (selected materials shown in Scheme1) we intend to derive a computational database that includes redox windows, solvation and stability. Detailed computations are required to compute stability of ions/molecules in the solution during electrochemical charge and discharge. Numerous parameters control the stability of redox shuttles and their cyclability, such as thermodynamic and kinetic processes. In order to understand the thermodynamic stabilities, computation of thermochemistry of likely decomposition reactions offers valuable assistance. Firstly, both free energies and enthalpies of possible reactions in solution phase provide information on the likelihood of such decomposition reactions (fragmentation, auto oxidation, rearrangements) and the design of redox compound. Secondly calculations of reaction barriers enable us to predict whether a particular reaction would proceed under specific reaction conditions. Rate constants decomposition reactions can be computed using this approach. We intend to compute the properties using density functional methods and validate their accuracies against high-level ab-ini tio methods for select cases. The stability of cationic or anionic species in the redox flow batteries are often controlled by the solvent effect and the understanding of their lifetime and reactivity vs. time and temperature is another very important aspect that we will explore using ab initio dynamics simulations. Note that this is computationally time consuming and require lengthy simulations. State-of-the-art quantum chemical calculations are a powerful tool in the search for new redox candidates. Prediction of computed redox potentials and stability of redox couples will enable experimentalists to avoid performing unnecessary experiments and hence reduce the cost for discovery. Existing molecules can be modified by ligand substitution, which can adjust the redox potential. Our research group has shown proof of this principle for silicon-based electrolytes previously (Assary et.al, J Phys Chem C 2011, 115, 12216). We have already established limited computational guidelines for selected organic molecules (quinoxaline) and sulfur (S8) for obtaining structure-electrochemical activity relationships, especially for the estimation of electrochemical windows. . From these studies, compounds with desired potential range, effect of electron withdrawing and electron donating groups, effect of salts, solvents on redox potential can be obtained. These studies will be further expanded to to include computational results for stabilities using chemical reactivity indexes and transition state theory. These results will be provided to JCESR collegues via PowerPoint presentation and to scientific communities via peer reviewed publications. Following list suggest some early breakthroughs from my research related to the energy storage of organic materials from computational studies: 1. Towards a molecular level understanding energetics in Li-S batteries using a non-aqueous electrolyte: A high-level quantum chemical study. Rajeev S. Assary†, Larry A Curtiss, Jeff Moore, Journal of Physical Chemistry C, 2014, 118, 11545-58. 2. Investigation of the Redox Chemistry of Anthraquinone derivatives using density functional study, Jonathan Bachman, Larry A. Curtiss, Rajeev S. Assary†, Journal of Physical Chemistry A, 2014, DOI: 10.1021/jp5060777. 3. Liquid Redox Active Molecules towards Non-aqueous Flow Battery, Jinhua Huang, Lei Cheng, Rajeev S. Assary, Anthony K. Burrell, Larry A. Curtiss, Lu Zhang, 2014, submitted. 4. Reduction potential Prediction of Some Aromatic Nitrogen Containing Molecules, Rajeev S. Assary†, Fikile R. Brushett, and Larry A. Curtiss, 2014, submitted. 5. BF3-Promoted Redox Activity if Quinoxaline in Aprotic Solvents, Emily Carino, Charles E. Diesendruck, Larry A. Curtiss, Rajeev S. Assary†, Fikile R. Brushett, 2014, submitted. Industry partnership: NONE Project URL: Requested allocation: 500000 Q1: 100000 Q2: 100000 Q3: 150000 Q4: 150000 Justification: Quantum chemical calculations will be performed using Gaussian 09 and CPMD softwares, both of them are available in LCRC computer clusters. The PI has extensive experience in effectively using these software packages and obtaining meaningful results in a timely manner. Gaussian 09 is scalable upto 64 processors. Mainly required to perform long and vast number of jobs. CPMD is a well parallelized software available in LCRC machines. Storage requirements: 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

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[LCRC Accounts] Project Request: Electric_Interface
by accounts＠lcrc.anl.gov 11 Sep '14

11 Sep '14

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: Kah Chun Lau Applicant's institution: ANL Applicant's division: MSD, CLS-LCRC Project Name: Electric_Interface Project title: Electrified Interfaces from First-Principle Studies Associated funding: DOE BES-CEES EFRC, DOE BES-JCESR Other Systems: Science: Electrified Interface of solid and solid/liquid electrolytes in electrochemical system is presently the subject of great interest to electric energy storage research at Argonne (i.e. BES-JCESR, BES-CEES-EFRC), and also among the scientific community. Within this wide area of research problems, the effect of external bias voltage on the interface at the atomistic scale is the basis of our fundamental understanding, design and application in this field. To include the external bias voltage in atomistic simulation based on first-principle study (DFT), the theoretical treatment with the application of a finite homogeneous electric field proposed by Nunes et. al. [1] is a reasonable and practical method based on DFT calculations. Within this proposal, the key parts of the proposed study will consists of three independent yet related topics: (I) the electrified interface of organic electrolyte/oxide, (II) electrified interface of water/metal, and (III) electrified oxide solid. For the case study of electrified interface of oxide/organic electrolyte, the well-known problem of solid-phase instability at external electric potential that exemplified by metal dissolution from manganese (Mn)-based oxide cathode surface that found in next generation Li-ion battery system [2] will be addressed. To go in parallel with our experimental colleagues, the modeled system will based on the spinel LiMn2O4 (LMO)/ GenII electrolyte (i.e. 1.0 LiPF6 in ethylene carbonate: ethyl methyl carbonate electrolyte with 3:7 ratio by weight) developed at ANL. For this system, the DFT atomistic simulation of Mn dissolution at anode interface has been performed by one of the PIs (K.C. Lau, MSD) [3]. In present proposal, the primary focus will be Mn desolvation, dissolution and diffusion at the cathode interface will be investigated. To simplify the model, the Ab Initio Molecular Dynamics (AIMD) simulation of LMO/electrolyte interface will be only based on the lowest energy LMO facet that yet to be determined. In addition, the effects of external electric field on this system (e.g. diffusion, desolvation, electronic properties, etc.) will also be investigated. The microscopic structure of the water/metal interface is still controversial and an active area of research. We propose to employ methods developed Sprik, Siepmann, Izekov and Voth [4,5,6] to generate realistic models of the bilayer of water on a metal surface. This approach employs molecular dynamics with a force-field that includes polarization to model the image dipole in the metal to determine an initial geometry for ab initio molecular dynamics to model reactions. The pre-equilibration by molecular dynamics allows the long range structure of the aqueous phase to equilibrate with field generated by the image dipole in the metal and the applied potential. The electronic structure calculations will exploit the Effective Screening Method implemented in OpenMX by Ohwaki, et al. [7] to model reactions on the metal/water interface under an applied electrical bias. This model will used 2D periodic boundary conditions and a semi-infinite effective medium to model the solven t outside slabs of water above slab of Pt. The slab of water will be 3 nm thick to include the water bilayer and a dozen layers of water to model the aqueous phase. Without the interface, the study of the effect of external electric field on a solid that present in electrochemical synthesis route is also an interesting yet not well been addressed. In this proposal, we will focus on lithium superoxide crystal that recently electrochemical been synthesized for the first time at ANL. From one of PIs’ (K.C. Lau, MSD) previous study [8,9], it has been shown that this oxide is semi-metallic ferromagnetic system originated from its open-shell 2p electrons of O2- molecules in crystal lattice. However the basic understanding of this system has been limited to weakly-correlated electronic structure description based on conventional DFT calculations that cannot accurately predict the ferromagnetic order of the correlated oxygen p-electrons in lithium superoxide. To resolve this issue, a systematic study of Quantum Monte Carlo (QMC) calculations of the magnetic and electronic states of this system will be carried out. From the proposed QMC calc ulations, the important U-values for the Hubbard-corrected DFT (DFT+U) will be determined. Project description: The project can be divided into three related problems: 1) Electrified Interfaces of spinel LMO >From a recent DFT calculations [10], it is found that the predominant low energy surfaces of LMO are (100), (110) and (111) facets. Therefore these surfaces appear to be a logical modeled system to start with. To address the problems that related to our experimental colleagues findings, the simulation of Mn dissolvation, dissolution and diffusion into electrolyte interfaces will be performed with and without the explicit solvent in the simulation. Subsequently the effect of external bias voltage (i.e. the external uniform electric field) on the LMO solid /organic solvent interface will be investigated using VASP code. 2) Electrified Water/Pt Interface The oxygen reduction reaction will be modeled on Pt(111) to evaluate the utility of OpenMX. This model will used 2D periodic boundary conditions and a seminfinite effective medium to model the solvent outside slabs of water above 1nm slab of Pt. The slab of water will be 3 nm thick to include the water bilayer and several layers of water to model the aqueous phase. We will model this reaction with and without an applied voltage. The initial model involve a hundred molecules of water and hundred atoms of Pt in a 10Å x 10Å x 40Å box, and the thermal equilibrated configuration will obtained based on classical MD atomic trajectory using LAMMPS code. 3) QMC validated DFT-U of Lithium Superoxide Magnetism Based on the DFT obtained lowest energy crystalline structure [8], the high-level QMC calculation of lithium superoxide crystal will be used to investigate the ferromagnetism and electronic properties of this system. Based on QMC data, the U-value that needs to compute Hubbard DFT-U calculations will be determined. In addition, the intrinsic spin-orbit effect and external electric-field on its electronic properties will be addressed. Calculation size: The smallest cells for which the effects of interest can realistically be simulated for LMO/electrolyte AIMD simulation will contain about five hundred atoms, with perhaps a 200 atom slab of LMO, and 300 atoms of electrolyte. All numerical shortcuts (gamma-point only, soft pseudopotentials) will be exploited. We expect to run on 256 processors. Of the calculations proposed here, the AIMD simulations (item 1) will have the largest CPU-time requirements per unit MD-time step of 1 fs. The AIMD simulations performed in NVT-ensemble simulations may require about 1 processor-hr per time step, for a cell size of about 500 atoms (using perhaps 256 processors). Obtaining a reasonably good MD statistics calculation may require of the order of 200 k processor hrs. Simulations of the 2D periodic water/Pt metal system (item 2) are expected to require of order 1 processor-minute per relaxation step or MD step. Considering three different interfaces sampling at a given temperature, and of order 2x10**5 steps for each case, the total time for this step would also be of order 100k processor hrs. Thus a 300k processor hrs is needed. For item 3 calculations, the most expensive calculation is QMC simulation that cost about ~ 100k processor hrs. For DFT+U calculations, about 100k processor hrs will be needed. Thus, requirements for the entire project are thought to be of order 700,000 processor hours. Industry partnership: Project URL: Requested allocation: 700000 Q1: 150000 Q2: 200000 Q3: 200000 Q4: 150000 Justification: VASP is well known to have scalability issues. Although it is very efficient code for models contains 100s of atoms, the parallel scalability for systems of this size is only 100s of cores. Although better parallel scalability can be obtained for larger models, the size scalablity becomes a major issue as O(N3) terms become a bottleneck in the simulation. The scalability of Abinit and Quantum Espresso is similar to that of VASP. OpenMX is an O(N) code with good parallel scalability. A recent publication by Duy and Osaki [11] has demonstrated the excellent parallel scalability of OpenMX to over a 100K cores on the K computer. Quantum Monte Carlo (QMC) codes are known to have good parallel scalability with poor size scalability. For example, Wagner et al. [12] demonstrated good parallel scalability of QWALK to 4 thousands cores of the Franklin supercomputer at NSERC. QMC will provide reference energies, which include all electronic correlation for comparison to the results of density functional approximations and determination of the U in DFT+U. LAMMPS is well known to have good parallel scalability References: 1. R. W. Nunes and X. Gonze, Phys. Rev. B 63, 155107 (2001). 2. C. Zhan, J. Lu, A.J. Kropf, T. Wu, A.N. Jansen, Y. Sun, X. Qiu, K. Amine, Nature Comms. 4, 3437 (2013) 3. K.C. Lau, J. Lu, L.A. Curtiss, K. Amine (in preparation). 4. J. I. Siepmann, M. Sprik, J. Chem. Phys. 102, 511 (1995). 5. S. Izvekov, G. A. Voth, J. Chem. Phys. 115, 7196 (2001). 6. J. Carrasco, A. Hodgson, A. Michaelides, Nature Mater. 11, 667 (2012). 7. T. Ohwaki, M. Otani, T. Ikeshoji, T. Ozaki, J. Chem. Phys. 136, 134101 (2012). 8. K.C. Lau, J. Greeley, L.A. Curtiss, J. Phys. Chem. C 115, 47, 23625 (2011). 9. J. Lu et. al. (submitted). 10. A. Karim, S. Fosse, K. A. Persson, Phys. Rev. B 87, 075322 (2013). 11. T.V.T. Duy, T. Osaki, Comp. Phys. Comm. 185, 777 (2014). 12. L.K. Wagner, M. Bajdich, L. Mitas, J. Comp. Phys. 228, 3390 (2009). Storage requirements: 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

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[LCRC Accounts] Yearly Allocation Request for Cat_Biomass
by accounts＠lcrc.anl.gov 11 Sep '14

11 Sep '14

Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Rajeev Surendran Assary Project Name: Cat_Biomass Division: MSD Project title: Computational Studies of Biomass Catalysis Associated funding: BES, EERE Other Systems: CNM Argonne, Blue Gene/P Argonne, NERSC Science: This computational project will be performed to gain fundamental understanding of the chemistry of biomass reactions and help to design catalysts that improve the efficiency of biomass conversion to transportation fuels or industrial chemicals. The project is an integral part of the computational modeling as part of the Computational Biomass Pyrolysis consortium funded by Energy Efficiency and Renewable Energy (EERE). Efficient chemical transformation of biomass is essential to produce sustainable energy and industrial chemicals. Conversion of biomass to useful chemicals include sequence of chemical transformation including, C-O bond cleavage and C-C bond formation. Project description: Main challenges facing the biomass conversion reactions are a plethora of undesired reactions and lack of efficient catalysts for various chemical reactions associated with biomass conversion process. Various reactions include dehydration, rehydration, isomerization, aldol/retro aldol reaction, ring opening/closing, carbon-carbon coupling, hydrogenation, and hydrodeoxygenation reactions. A detailed understanding of the chemistry of both desired and undesired reactions, together with the understanding of catalysis is essential for catalyst design for efficient biomass conversion. Our principle objective here to identify guidelines to search for efficient C-O bond cleaving and C-C bond forming catalysts from first principles to assist experimentalists to discover efficient catalysts. Catalytic C-O bond cleavage and C-C bond formation Efficient catalytic cleavage of C-O bonds of biomass molecules is crucial to the conversion of biomass to transportation fuels and industrial chemicals. Recently, we have explored a series of lanthanide trivalent metal triflates as potential catalysts for the C-O bond cleavage in ionic liquids using combined quantum chemical methods. This theoretical finding is supported by the experimental studies. The metal triflate catalysts were found to be active for a series of ether substrates when used in tandem with hydrogenation catalysts (Pd/Alumina), etheric substrates afford industrially useful alcohols. In this proposal we would like to identify most efficient metal triflate catalysts for the conversion of ethers to alcohols and subsequently to alkanes using quantum chemical methods. This information regarding the catalysis can be then feed into experimentalists for testing. For computations, the density functional theory (DFT) will be used to compute various catalytic descript ors such as binding of ether substrates with the catalysts and the activation energy required to cleave the C-O bonds of various substrates. Calculations will also be performed to understand detailed reaction mechanisms to identify undesired reactions and to improve the efficacy of the catalyst by rational design. Various metal triflate catalysts with central metal atoms (Z=22 to Z=92) will be considered for this study. The oxidation states from +3 to +6 will be considered. Due to bulkiness and bidentate nature of the triflate ligands, upon coordination with highly positive metal ions (for example Nb (V) or Mo(VI)), it is likely that the first coordination layer of the central metal ion may be saturated by the triflate and the binding of ether-substrate and subsequent catalysis may be unlikely. Here, we propose to model such scenarios by mutating the ligands of M(OTf)n (n=4 to 6) by less bulky mono anionic systems ( for e.g. F-, CN- etc.) and compute the C-O bond breaking efficacy using DFT. Catalytic C-C coupling: Second category of C-C coupling reactions that we would like to address is Aldol reaction combined with hydro cyclo addition reactions. The reaction sequence here is aldol reaction, hydrogenation in tandem with cyclo-addition reactions. Use first principle-based calculations (density functional theory, ab initio methods) to understand possible reaction pathways for converting furans and low molecular weight carbohydrate molecules (C1 to C4) obtained from biomass pyrolysis to C8-C21 distillate class compounds. Explore catalytic reactions (reaction energetics of individual reactions steps associated with the reaction pathway will be computed) that can increase the carbon chain length by coupling reactions using first principles calculations. This task will be carried out in close collaboration with National Renewable Energy Laboratory due to their extensive experience in vapor phase upgrading and catalyst synthesis. Software requirement: Gaussian, VASP, and CPMD/CP2K Performance for the past years: During the past four years we have gained significant progresses to understand the thermodynamic feasibilities of important reactions involve in the transformation of biomass to platform chemicals. Significant computational progresses were made in the molecular level understanding of biomass conversion reactions such as fructose to hydroxy-methyl-furfural, furfuryl alcohol to levulinic acid, polymerization of furfuryl alcohol, pyrolysis of glucose, isomerization of aldoses, catalytic C-O bond cleavage, and liquid phase catalytic hydrogenation. We gratefully acknowledged the grants for the computer time by LCRC for the past four years. We have made excellent use of the allocated computational resources during past five years. Following website lists all 22 peer reviewed publications as results of our computational studies: http://www.energyfrontier.us/author/assary-rajeev-s Industry partnership: None Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 1200000 Q1: 300000 Q2: 300000 Q3: 300000 Q4: 300000 Justification: Gaussian 09/VASP software is scalable up to 64 processes. Here main bottle neck is large number of calculations and long execution times than the parelliization. CPMD and CP2K are high performance software packages, scalable to 64 nodes. Storage requirements: Thank You, The LCRC Accounts System

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[LCRC Accounts] Yearly Allocation Request for Li_air_battery
by accounts＠lcrc.anl.gov 11 Sep '14

11 Sep '14

Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Kah Chun Lau Project Name: Li_air_battery Division: MSD Project title: Computational studies of Li-Air battery components Associated funding: DOE-BES CEES-EFRC, DOE-EERE Other Systems: CNM Science: To date, today's battery researchers and developers have not yet been able to unlock the theoretical potential of Li-Air battery into practical application due to : (1) the unstable non-aqueous electrolytes that easily oxidized and decomposed during discharge/charge, thereby seriously limiting cycle life; (2) during discharge, the solid Li2O, Li2O2, and LiO2 and insoluble Li2O2 and/or Li2O products are deposited on the surface or within the pores of the cathode, thereby clogging the pores, restricting oxygen flow and shut down the electrical conductivity; (3) poisoning of the lithium electrode due to oxygen crossover destroys the integrity and functioning of the cell; and (4) commonly used cathode catalysts, such as metals, metal complexes, and metal oxides, do not access the full capacity of the oxygen electrode or enable sufficiently high rates. Thus in the computational studies, these problems will continue be addressed and explored based on state-of-the-art ab initio atomistic modeling techniques that work closely with experimental colleagues at ANL. This is a project which will be in its 1st year that was awarded under the renewal of DOE-BES CEES-EFRC program that led by Argonne. Project description: In the coming fiscal year (FY2015), we need 1200 000 core-hour to complete our project. We will complete our current on-going work and continue to explore different problems in Li-air batteries based on experimental input from our colleagues at ANL. To complete the current ongoing study (i.e. the effects of K-doping in carbon electrode to facilitate ORR in Li-O2 cell, solvation and solubility of Li2O2 and LiO2 molecule in DME electrolytes), our experience indicates that 100, 000 hours is required. For our new study at FY2015, the computational methods will involve largely AIMD (CPMD, VASP, CP2K) and DFT method (Gaussian09, VASP, Quantum Espresso). For Gaussian09, the DFT calculation scales well up to 8-16 processors and for 4-6 nodes is the optimal number of nodes for geometry optimization for system size below 100 atoms. We will require about 200,000 core hours to study the Nuclear Magnetic Resonances (NMR) properties of Li2O2 and LiO2 stoichiometric clusters at different electrolytes in solution phases. To extend our previous solvation study on LiO2 in DME electrolyte, we will study extend our study on the stability and solvation of LiO2 in different dielectric media with the representation of various electrolytes-based solution (e.g. DMSO, DMA, ionic liquids) based on both combined AIMD simulation and quantum thermochemistry calculations using VASP and Gaussian09 code. For a single Γ-point calculation with a total atom ~ 300-400 atoms AIMD simulation, a parallel efficiency of ~ 60% -75% can be achieved using 256 cores. Thus to explore a moderately large systems (~ 300 atoms) with simulation time up to ~ 5ps in 1 fs time step, 50 000-100 000 core-hour is needed to perform the tasks for each electrolyte. To study a few chosen bulk electrolytes AIMD simulation, this will need 500 000 core-hour to complete these computational intensive simulations. In addition to the studies on electrolytes, we will spend our significant efforts on LiO2 studies that directly related to our ANL colleagues’ future plan on the experimental studies in LiO2. Based on our understanding of LiO2 crystalline solid, we will carry out a systematic study on various low indexes stoichiometric and non-stoichiometric surfaces of LiO2 (in vacuum and with implicit solvent) to predict its thermodynamic equilibrium Wulff crystalline shapes based on DFT calculations which will take 150 000 core-hour. To extend our basic understanding of the crystal growth of LiO2, we will carry out a systematic study of a promising Li-metal alloy as a template growth for LiO2 crystal. Thus to construct a reasonable DFT model, a simulation cell of about 200-300 atom surface calculations within an optimal DFT accuracy is necessary, and it needs an extra 250 000 core-hour in this problem. In conclusion, this will need 1200 000 core-hour (1.2 Million core-hour) to complete all these problems in FY2015. Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 1200000 Q1: 300000 Q2: 300000 Q3: 300000 Q4: 300000 Justification: For the details and evidence how to use the hours effectively, please see the project description and project report (FY2014). Further details of the scaling and the performance of the codes can be found as follows: (1) VASP: http://cms.mpi.univie.ac.at/vasp/vasp/Performance_parallel_code_on_various_… (2) CPMD: http://cpmd.org/documentation (3) Gaussian09: http://www.gaussian.com/g_prod/g09_glance.htm Storage requirements: Thank You, The LCRC Accounts System

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[LCRC Accounts] Yearly Allocation Request for XRayFuelSpray
by accounts＠lcrc.anl.gov 11 Sep '14

11 Sep '14

Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Daniel Duke Project Name: XRayFuelSpray Division: ES Project title: Fuel Injection and Sprays Studied Using X-Ray Diagnostics Associated funding: DOE-EERE Other Systems: None Science: At the Advanced Photon Source Sector 7-BM at Argonne National Laboratory, we are presently engaged in an ongoing investigation of sprays in high-pressure fuel injection systems using X-ray diagnostic techniques. This work is funded by DOE-EERE. An improved understanding of spray formation physics is essential to the development of more efficient engine technology. As a part of this ongoing research, we are investigating the presence of cavitation phenomena in fuel injection systems and how these phenomena impact spray formation. Cavitation is a problem in fuel injection systems that operate under high pressure. At the Advanced Photon Source, we are undertaking a series of experiments to develop novel methodologies to measure cavitation inside fuel injectors and model nozzles using a range of x-ray techniques. In order to develop these novel experimental techniques, it is necessary to have an accurate and detailed prediction of the cavitation zones inside the model nozzle at precisely defined boundary conditions, to provide a common point of comparison for different experiments. To achieve this, numerical simulations of the fluid flow are necessary. The prediction of cavitation in a turbulent flow at high pressure requires the use of a high-resolution three-dimensional mesh with high levels of local refinement. As such, the computation times for these highly resolved meshes are beyond the reasonable capability of a desktop computer. High-performance computing allows us to perform these simulations. Cavitation simulations performed using OpenFOAM over the last two years under this project have been extremely useful in guiding our experimental plans. The data have also provided a useful validation tool for improved model development. Continued improvement of high-fidelity LES in simplified submerged nozzle geometries allows us to better understand the fundamentals of nozzle cavitation. Secondly, the cavitation simulations in realistic production fuel injector geometries assist in the interpretation of x-ray phase contrast imaging of in-situ injector cavitation. In the following year, we plan to extend high-fidelity cavitation simulations by undertaking longer simulation times in order to capture lower-frequency hydrodynamic phenomena which we have observed in our experiments. Since most LES are only run until for a few milliseconds delta-T until a sufficiently steady solution is achieved (and statistics are suitably converged), low frequency oscillations (below 1 KHz) have not before been studied using simulations. Improvements in efficiency will allows us to pursue longer run-time simulations. We are currently investigating the application of x-ray fluorescence measurements for cavitating nozzle flow. This technique has the advantage of allowing us to measure both liquid density and dissolved gas concentration simultaneously. Such data will be highly valuable in the development of non-condensable gas modeling in cavitating flows; this is a problem of great interest to the modeling community. The combination of high-resolution numerical simulations and x-ray measurement techniques will improve our understanding of cavitation in fuel injection systems, increasing the impact of our work. Over the first quarter of the next year, the project will incorporate a new sub-task focusing on gaseous jets at high injection pressure conditions. CFD calculations of the entire injection event (including opening and closing transients) will be performed with the CFD code CONVERGE and the numerical results will be validated against x-ray radiography data. The nozzle internal flow will be also simulated in order to improve the accuracy of inlet boundary conditions. The main effort will be aimed at the characterization of the shock structure in the under-expanded region and its effect on jet propagation and mixing with air. Over the next year, the X-ray Fuel Spray project will also expand to include more tomographic x-ray radiography, particularly of gasoline direct injection sprays. Moving from line-of-sight radiography to tomography requires tomographic reconstruction of the data created at APS. We intend to use Blues (and Fusion) to perform rapid turnaround high-resolution reconstructions using the TomoPy software developed at APS. We may consider the purchase of dedicated nodes for this purpose in future. Project description: The cavitation modeling component of the project is being performed using the OpenFOAM framework. A number of state-of-the-art numerical solvers have been implemented in OpenFOAM; namely incompressible-liquid and fully compressible homogeneous relaxation cavitation models and more recently a fully compressible homogeneous relaxation cavitation model which includes non-condensable gas modeling (HRMFoam). These codes were developed by Schmidt et al at the University of Massachusetts-Amherst, and we continue to collaborate with them on code development and efficiency improvements. In the last year, we have made some substantial improvements to the cavitation model and the parallel efficiency of its implementation on Blues/Fusion. With the support of LCRC technical staff and our collaborators at the University of Massachusetts-Amherst, we have implemented a custom build of OpenFOAM-3.0 on Blues against the system native MPI, and we have made the necessary changes to the HRMFoam solver’s source code in order to move from the older OpenFOAM-1.6 to the new 3.0 framework. This has led to substantial gains in parallel performance; up to 20% on 32 cores and 12% on 64 cores on Blues. A scalability study has been performed with the new code, and details are given in the Large Allocation Efficiency statement. In the new OpenFOAM-3.0 build, we have successfully implemented both Large Eddy Simulation (LES) and Realizable k-epsilon (KE) turbulence models. Furthermore, we have implemented code which allows us to take virtual projections of the three-dimensional simulations so that they may be quantitatively compared with the x-ray experiments. In the following year, we plan to extend high-fidelity cavitation simulations by undertaking longer simulation times in order to capture lower-frequency hydrodynamic phenomena which we have observed in our experiments. Improvements in efficiency will allows us to pursue longer run-time simulations. We also intend to simulate the effects of varying pressure and flow rate on cavitation, in order to compare against new x-ray fluorescence data from APS. The gas jet simulations which we plan to undertake in Q1 are performed with the CONVERGE CFD software, its use is already well established at LCRC. Tomographic reconstruction of gasoline direct injection spray measurements from APS will be conducted using the TomoPy software package developed at APS. We intend to run single-node jobs to efficiently perform multiple reconstructions of large (multi-GB) datasets. We have also successfully compiled a Paraview server on our Fusion dedicated nodes which allows us to rapidly visualize the results of our simulations and reconstructions. Using Blues and Fusion will allow us to achieve rapid turnaround of results during beamtime. This will be a significant aid to the experimental program. As the quantity of tomography work increases, we may consider purchasing more dedicated nodes. Industry partnership: not applicable Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 600000 Q1: 195000 Q2: 135000 Q3: 135000 Q4: 135000 Justification: Our requested allocation for next year will exceed 0.5M core-hours in order to encompass the gas jet simulations in Q1 and tomographic reconstruction work in Q2-4. The majority of core hours will still be dedicated to OpenFOAM simulations, which will be undertaken on both dedicated Fusion nodes and also on Blues, using OpenFOAM-3.0. We have demonstrated notable improvements in scalability on Blues as detailed above. A scalability study of OpenFOAM-3.0 performance with multi-million cell meshes has been undertaken, demonstrating excellent linear scalability. We observe 81% efficiency relative to single-CPU performance, scaling linearly up to 320 cores (20 nodes) with a 15-million cell mesh (a typical upper limit). We have implemented Scotch decomposition in order to ensure good load balancing & minimization of cross-processor communication boundaries. The present OpenFOAM simulations use static meshes, so load rebalancing at runtime is not a concern. We intend to run typical job sizes of 64 to 128 cores; smaller than the maximum job size for which good scalability has been demonstrated. Further details regarding scalability studies can be obtained by contacting the project PIs. Storage requirements: At the present time, we do not expect to exceed our project storage space allocation. Regarding data storage for tomographic reconstruction, the project space will only be used for temporary storage. Data will be moved to our own file servers once reconstructions are completed. Thank You, The LCRC Accounts System

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