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

[LCRC Accounts] Yearly Allocation Request for ElectrolyteRedoxFlow
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: Lei Cheng Project Name: ElectrolyteRedoxFlow Division: MSD Project title: discoveries of electrolyte for redox flow batteries Associated funding: JCESR Other Systems: NERSC Science: To meet global energy demand, renewable energy sources such as solar and wind energy are being developed and utilized. The increased use of wind and solar energy will challenge the grid’s ability to provide a stable electrical supply around the clock. Grid energy storage can be used to shift load from peak to off-peak hours and redox flow batteries are of particular interest to perform this load leveling. Redox flow batteries differ from classical batteries in that energy is stored in the liquid electrolyte in separate liquid reservoirs instead of in the electrode. This bypasses common electrode degradation issues observed in lithium ion batteries and makes the battery systems more durable and scalable. However, all flow batteries based on aqueous electrochemical couples are limited by the electrochemical properties of water which is only stable within a small potential window (typically 1.2-1.6 V) outside of which water electrolysis occurs. This means that redox- flow battery suffers from lower energy density. In order to increase the energy density, the current or potential must be increased. Employing non-aqueous electrolytes offers a wider window of electrochemical stability, enabling flow batteries to operate at higher cell potentials (>2 V) and eliminating this low energy density limitation. Among various fundamental science and engineering challenges in the design of more efficient redox flow batteries, discoveries of appropriate redox couples that operate at higher cell voltage will lead to greater system energy densities and higher energy efficiencies. It is also one of the important missions of the energy storage hub Joint Center for Energy Storage Research (JCESR). Project description: In this renewal work, we will continue focusing on fundamental properties of transition metal complexes as redox active molecules for non-aqueous redox flow battery application. In collaboration with experimental group (Prof. Thompson, University of Michigan), we have previously studied redox windows of some novel compounds. We now study the solubilities of these compounds in non-aqueous solutions as the capacity of this type of battery is directly proportional to redox window and concentration of active compound in solution. Insight gained from these studies will greatly guide design and synthesis of the compounds experimentally. In previously proposed work, we have successfully determined the B3LYP/6-31+G* and BP86/6-31+G* combinations as proper computational treatments for these system. The same methods will be used to calculate solvation energies of Cr, V, Mn and Fe based novel compounds. These energies will be calculated using both implicit continuum models such as PCM, CPCM and SMD methods, as well as explicit model with actual solvent molecules added to the quantum calculations. These solvation energies will then be compared with experimentally measured solubilities of the compounds to determine correlation between the two. Calculations with explicit solvent molecules will also be performed to further validate accuracy of the implicit model calculations as well as provide more insights on coordination details of the metal complexes by solvent molecules. Recently, interesting solubility trends of metal complexes in different binary organic solvents have been observed experimentally (private com munication). We will also guide our research efforts towards providing physical understandings of the observed experimental results. All calculations will be performed using Gaussian and NWCHEM. These two code packages are both considered very efficient and reliable for quantum chemistry calculations. Gaussian is not very scalable but it provides really robust geometry optimizer and the G3/G4 methods are built-in. NWChem is very scalable especially for higher level calculations such as coupled cluster methods and perturbation theories. After interesting molecule candidates and appropriate calculation methods are identified, derivatives of these molecules will be subject to high-throughput screening. The high-throughput screening will be performed using NERSC supercomputers. Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 600000 Q1: 150000 Q2: 150000 Q3: 150000 Q4: 150000 Justification: The size of molecules we propose to study is very typical for the two computational software (Gaussian and NWChem) so they scale reasonably well for most DFT calculation. The higher level calculations will consume more memory as well as computational time. The NWChem code uses a globally-shared memory system, therefore one can request and utilize more memory through node parallelization. Storage requirements: Thank You, The LCRC Accounts System

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New LCRC report submitted for metadissolve
by support＠lcrc.anl.gov 11 Sep '14

11 Sep '14

Full project report at https://accounts.lcrc.anl.gov/reporting/project/2014/?project=metadissolve

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[LCRC Accounts] Yearly Allocation Request for Solar_Forecasting
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: Edwin Campos Project Name: Solar_Forecasting Division: EVS Project title: Multi-Model Machine-Learning Solar Forecasting Technology Associated funding: DOE EERE SunShot Other Systems: None. Science: The objectives of this 3-year project (started on Aug. 2013) are as follows: -Step 1: Perform seminal research to improve modeling and forecasting of solar irradiance. -Step 2: Apply research results obtained from Step 1 (previous) to develop solar power forecasts. -Step 3: Validate developed solar forecasts to meet target values of pre-existing standard metrics. Project description: Failures to predict solar energy generation accurately will undoubtedly constrain the national expansion of renewable energy. There are several technology barriers -- such as forecast inputs integration, forecasts output integration, scalability of forecasting tools, and numerical representation of relevant cloud processes -- that must be overcome for improving solar forecast accuracies to a useful level, if solar energy were to be become a dependable source of energy. This project proposes to overcome these barriers by using novel machine-learning algorithms, big-data analytics, and hi-performance computers. The project will demonstrate that transformational improvements are possible on solar forecasting -- for periods between 0 to 6 hours (including power ramps) and the day ahead -- by determining optimal combinations for observations of thermodynamic profiles measured over a solar power plant, measured cloud motions in the area (e.g., from remote sensing observations at high resolution) and routine forecast outputs from numerical weather models. During the 1st year of the project, we developed computational modules in IDL, Matlab and Fortran. Some of these now run in single core mode on Fusion. Since there was no IDL available on Fusion, we supported the purchase of an IDL software license for the LCRC system, which is expected to be available before the beginning of FY2015. During the following years of the project, we will implement parallel processing of various solar forecasting codes to generate 0-47 hour forecasts over multiple sites across the USA. Industry partnership: IBM, Northrop Grumman, ISO-NewEngland, 3Tier, Green Mountain Power, Tucson Electric Power, Petra Solar, California ISO, JUWI energy, Prime Solutions Inc. Energy Engineering. Project URL: http://solarhighpen.energy.gov/project/ibm_thomas_j_watson_research_center_… Current FY Hours Used: undetermined amount New FY Requested allocation: 360000 Q1: 60000 Q2: 80000 Q3: 100000 Q4: 120000 Justification: Storage requirements: Thank You, The LCRC Accounts System

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[LCRC Accounts] Yearly Allocation Request for lith_ox_md
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: John Russell Project Name: lith_ox_md Division: MSD 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 microstructu ral 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 initial 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. We are also developing a variable charge lithium-oxide molecular dynamics potential suitable for modeling lithium superoxide, lithium peroxide, and Li2O. The computational cost of this method is estimated as 25x as expensive as a Buckingham pair potential, but with much greater flexibility to model different lithium-oxide stoichiometries. Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 400000 Q1: 100000 Q2: 100000 Q3: 100000 Q4: 100000 Justification: LAMMPS is a linear scaling molecular dynamics code. We will be using the Wolf summation potential to model electrostatics, which is very important due to the fact that FFT methods for electrostatics such as PPPM and PME are NlogN scaling. The Wolf summation is directly incoporated into our variable charge model. The variable charge itself has costs due to charge equilibration, which should put it on par with MEAM and AIREBO. In LAMMPS these methods are compared to a Lennard-Jones (LJ) potential as a benchmark reference (LJ = 1.0, Buckingham ~ 1.0). MEAM is rated at 16.5x and AIREBO at 40.6x. This is primarily due to loops over second nearest neighbors. Therefore, we expect the potential to be in the range of 25x scaling. Storage requirements: Thank You, The LCRC Accounts System

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[LCRC Accounts] Yearly Allocation Request for Drude
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: Benoit Roux Project Name: Drude Division: BIO Project title: Development and validation of new polarizable force field for molecular dynamics Associated funding: LDRD on force field with Subramanian Sankaranarayanan (number not out yet) NIH grant from NIGMS R01-GM072558: Polarizable Force Field For Proteins and Lipids Other Systems: BG/P, XSEDE, Anton, kbt, Beagle, Blue Waters Science: The functional form and parameters of a new force field accounting for induced polarization in molecular dynamics simulations must be developed, optimized, and validated for various biomolecular systems. We are mainly interested in ions binding to proteins at this point. Project description: Ions play indispensable roles in the structures and functions of biologically important molecules, many biological processes are also found to be ion-specific. Thorough interpretations of such ion-specificity require models that accurately treat electrostatic interactions between ions and their biological environments, which often involve polarization effects at different magnitudes. In the past several years, a significant number of studies have been published in scientific journals investigating the ion-protein interactions. A large portion of these molecular dynamics (MD) simulations are based on force fields using simple-point representations for one atoms or even for the entire chemically/physically importation groups, for example, the CHARMM, OPLS, GROMOS, and the AMBER force fields. Limitations are often seen in MD simulations employing these force fields and cannot be improved by further parameterization. Due to their underlying assumption of the fixed interaction-potential function, these models are not capable of reflecting the polarizable nature of atoms and thus failed in the cases when the polarization effects are prominent. Towards the goal of providing a comprehensive and accurate description for the behaviors of ions interacting with macromolecule, in the next allocation cycle, we will focus on improving polarizable ion force fields based on the classical Drude oscillator models. The Drude polarizable force field has been implemented in the program NAMD. It runs efficiently, at a computational cost comparable to that of non-polarizable force fields (slower only by a factor of about 1.4). This study will provide a systematic protocol by employing a wide range of target data. Besides the conventionally employed benchmarks in parameterization such as the gas-phase ion-small molecular cluster interactions and the experimental measured condensed-phase properties, the proposed study will also incorporate QM binding energy calculations for a wide spectrum of proteins. Specifically, we will improve models for biologically important ions interacting with proteins, including the alkali cation Na+, K+, a lkaline earth metal cations Ca2+, Mg2+, and transition metals Zn2+ and Ba2+. In addition, we hope that the approach employed will help initiating and facilitating a systematical approach for evaluating force field performances, thus allowing scientists resolving the functions and behaviors of ions in biological systems more efficiently and with higher confidence. In the propose study, we will perform MD simulations and QM interaction energy calculations for a large number of ion-binding proteins (10 different proteins for each ion type) and utilize these data as the benchmarks in the parameter optimization process. Allocation on fusion at LCRC of the Argonne National Lab is therefore requested to accomplish this project. Industry partnership: Project URL: http://thallium.bsd.uchicago.edu/RouxLab/ Current FY Hours Used: undetermined amount New FY Requested allocation: 1000000 Q1: 250000 Q2: 250000 Q3: 250000 Q4: 250000 Justification: We are mainly using Gaussian to compute binding energies of ion to proteins sites from a set of configurations previously generated with classical molecular dynamics. On average these configurations have 50-100 atoms, so the QM calculations are substantial. While the computations are extensive, Gaussian runs well on fusion and it well optimized. Storage requirements: 100 GB Thank You, The LCRC Accounts System

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[LCRC Accounts] Yearly Allocation Request for mpich_abi
by accounts＠lcrc.anl.gov 10 Sep '14

10 Sep '14

Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Ken Raffenetti Project Name: mpich_abi Division: MCS Project title: MPICH ABI testing Associated funding: Other Systems: We have access to a test cluster hosted by Intel for the purposes of ABI testing. There are no time quotas on this machine. Science: Project description: The MPICH ABI Compatibility Initiative is a collection of MPICH-derived MPI implementations with and explicit goal of maintaining ABI compatibility across each other. This project and associated allocation will be used to provide our industry partners with access to a supported install of the latest MPICH for ABI testing purposes. Industry partnership: The MPICH ABI Initiative is a collaboration between ANL, IBM, Intel and Cray. The goal of this project is to be able to demonstrate publicly that our software is compatible and working at scale. Project URL: http://www.mpich.org Current FY Hours Used: undetermined amount New FY Requested allocation: 100000 Q1: 25000 Q2: 25000 Q3: 25000 Q4: 25000 Justification: Storage requirements: Thank You, The LCRC Accounts System

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[LCRC Accounts] Yearly Allocation Request for 1atomCat
by accounts＠lcrc.anl.gov 10 Sep '14

10 Sep '14

Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Ujjal Das Project Name: 1atomCat Division: MSD Project title: Supported Single-Site Catalysts for Activation of Small Molecules Associated funding: BES Chemical Sciences Other Systems: CNM Carbon cluster - 100,000 cpu hrs. Science: This proposal requests a renewal of our previous proposal titled "Supported Single-Atom Catalysts for Activation of Small Molecules". The computational resources from the previous allocation were used to study the structure of catalyst active site of silica supported first-row transition metal catalysts (M/SiO2, M = Fe, Co, Zn) and reaction mechanisms of alkane dehydrogenation and alkene hydrogenation. In particular, we identified key defect sites on amorphous silica surfaces as binding sites for metals. We have also identified novel mechanisms for H-H and C-H bond activation in H2 and propane by single-site silica supported Fe(II), Zinc(II), and Co(II) catalysts. The current proposal requests for additional resources which will be used to investigate catalytic non-oxidative coupling of methane. The discovery and development of large reserves of shale gas, consisting of mostly methane, ensures that the selective utilization of methane will remain a target for large scale energy production. Any approach which can incorporate methane into transportable material for fuels and fine chemicals would be a dramatic breakthrough for the energy sector. Our approach is to study the fundamental reaction methane + olefin = larger alkanes. Mechanistic insight into the fundamental processes of methane interaction with the metal and subsequent addition to alkenes will guide the development of new single-site catalysts that are thermodynamically compatible and exhibit activity and selectivity required for practical applications. Project description: For methane homologation, density functional calculations will be used to investigate all possible reaction pathways leading to C-C coupling such as (1) activation of methane by metal catalyst followed by alkene insertion or (2) addition of alkene followed by methane insertion. Mechanism of possible side reactions that may reduce catalyst selectivity will be studied. They include dehydrogenation of the product alkane, polymerization of alkene precursors, and formation of aromatics. Mechanistic insights obtained from these studies will be used to screen numerous single-site catalysts. In particular, the calculations will focus on significantly lowering the activation barrier for C-C coupling while increasing the activation barrier for alkane dehydrogenation to ensure high activity and selectivity for methane homologation. We will perform density functional theory (DFT) calculations to determine structure, bonding, and reaction energies of the system. 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. The Nudged Elastic Band (NEB) method of Henkelman and coworkers will be used to calculate transition states and activation barriers for formation of different surface species. Surface phonons will be calculated for accurate estimation of reaction free energies. We will primarily use the DFT code implemented in VASP (for periodic calculations) and Gaussian package. Both VASP and Gaussian run in parallel mode. For the MPI version of VASP, increased efficiency is observed up to 32 processors. The Linda version of Gaussian scales up to 32 processors. Energy optimization in VASP takes approximately 750 CPU hours and we plan roughly 200 of such calculations. Hessian (second order energy derivative) evaluation takes roughly 1600 CPU hours and we plan to run 50 of these calculations. Optimization and Hessian evaluation using Gaussian program take approximately the same time for model clusters. We estimate that we will have to run a total of 300 Gaussian calculations, each taking 400 CPU hours. So our total request is 350,000 core hours. Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 320000 Q1: 80000 Q2: 80000 Q3: 80000 Q4: 80000 Justification: Storage requirements: Thank You, The LCRC Accounts System

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[LCRC Accounts] Yearly Allocation Request for anl-dcc
by accounts＠lcrc.anl.gov 10 Sep '14

10 Sep '14

Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Tsung-Shung Lee Project Name: anl-dcc Division: PHY Project title: Dynamical coupled-channel analysis of hadrons at Argonne Associated funding: DOE Other Systems: NERSC Science: This project will develop theoretical approaches for studying the spectrum and structure of excited baryon states within the fundamental theory of strong interaction; Quantum Chromodynamics (QCD). The results will provide information for advancing our understanding of strong interactions and structure of visible matter in universe. This is part of ANL's effort to achieve a DOE milestone HP7. Project description: In 2013-2014, we have completed a 8-channel analysis which extract nucleon resonances from data of pi-N and gamma-N reactions. In 2015, we need to continue this effort to extract N-N* form factors for testing the hadron structure calculations using Lattice QCD and various QCD-based models. In 2014, we have also extended our coupled-channel model to include the strangeness S=-1 channels to extract hyperon resonances. In 2015, we will apply this model to make predictions for new experiments on kaon-nucleon reactions at the new hadron facility J-PARC in Japan. The computations involve solving a large set of coupled-channel integral equations and searching for parameters to fit the world data of meson production of pion-nucleon and photon-nucleon reactions. The calculations account for eight meson-baryon channels and cover energies up to invariant mass W= 3 GeV. Large complex-matrix (1000 by 1000) need to be inverted many times in chi**2-fit to very extensive data (about 110,000 data points) . Standard fortran codes have been developed to perform parallel computations with the facilities at LCRC. The project will have 4 members. Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 50000 Q1: 15000 Q2: 15000 Q3: 10000 Q4: 10000 Justification: Storage requirements: Thank You, The LCRC Accounts System

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[LCRC Accounts] Yearly Allocation Request for Multicomp_Nanopart
by accounts＠lcrc.anl.gov 10 Sep '14

10 Sep '14

Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Sanjubala Sahoo Project Name: Multicomp_Nanopart Division: CSE Project title: Next Generation of Multicomponent Nanocatalysts: Computational Studies Associated funding: Strategic Initiative on Material for Energy (LDRD 2012-123-R1) Other Systems: None Science: The goal of this project is to explore, understand, and characterize, through modeling and simulations, the complex correlations between the size, composition, structure, thermal properties, electronic features, and chemical reactivity of multicomponent nanoparticles. The central aim is to aid the ongoing experimental effort currently underway at CNM and CSE on synthesis of novel heterogeneous - primarily binary and ternary metallic - nanocatalysts with superior activity and selectivity. Among the targeted catalytic transformations are selective hydrogenation of unsaturated hydrocarbons and aldehydes, which are the processes of importance in various chemical technologies including those relevant to novel sources of energy. Project description: Our aim is to study the structural, energetic, electronic, and catalytic activity and selectivity of elemental and multi-component transition metal nanoparticles both in gas phase and supported on substrates. Among the targeted nanocatalysts are Pt with deposits of Co, Ni, Fe, and Pd cations (the work on has been initiated already). Our studies have been extended to semi-infinite slabs of different transition metals such as Pt, CoPt3, FePt, FePt3 and others. The candidates for catalytic transformations (these systems will be tested) are the selective hydrogenation of unsaturated aldehydes such as citral with and without the vicinity of modifying ligands such as metal cations and primary alkylamines where the modifiers can be used to tune the catalytic activity and selectivity of the nanocatalyst for citral hydrogenation reaction. The experimental investigations with respect to the catalytic functionality of nanocatalysts are currently undergoing. We will be dealing with the following issues within the planned studies. 1) Use of size, structure and composition of the nanocatalysts as "knobs" for tuning their activity and selectivity for the hydrogenation of unsaturated aldehydes. In this respect, computations have been performed for finite size systems (55-atom elemental and binary cuboctahedral clusters). These studies have been extended to (001) and (111) surfaces of bulk crystal. 2) To study the effect of modifiers on the catalytic functionality of transition metal nanocatalysts, Fe dopants have been used where the effects of increased concentrations of both neutral and charged Fe dopants will be studied on the catalytic functionality of Pt nanocatalysts. Already some calculations have been performed in this direction where the energetics for different adsorption conformations have been studied as a function of concentration and location of Fe dopants with a preadsorbed citral on Pt55 cuboctahedron. We also plan to study the effect of alkylamine on the catalytic functionalty of Pt nanocatalysts, where we will be dealing with the adsorption energetics of amines as well as its concentration. The calculations in this regard have been partly performed. In addition, we will also be addressing the issue related to the simulataneous adsorption of Pt55 nanocatalyst by Fe and amines on the selective hydrogenation of citral. 3) To use the Infrared (IR) spectra as a tool to identify the actual adsorption conformation of citral on pure and modifier covered Pt nannocatalysts as observed in measurements. We have obtained a good agreement between the computed and the measured spectra for gas-phase as well as the supported citral. The computational studies of the structural, energetic, and electronic structure aspects will be performed using density functional theory. The packages that will be utilized include NWChem (uses plane wave and localized basis sets), VASP (uses plane wave basis sets) and Crystal. Naturally, we will benefit from the efficient scaling of the codes and take advantage of it in order to explore systems with still increasing number of atoms. Thus in our project: 1) The study of the properties of the nanocatalysts for different size of nanoclusters, ranging from a few tens to a few hundreds of atoms, and 2) the effect of different surfaces and composition of the supporting substrates is a priority research program which suits well with the high-performance infrastructure of the Fusion computational resources. Industry partnership: Project URL: http://blogs.anl.gov/major_initiatives/materials-for-energy/ Current FY Hours Used: undetermined amount New FY Requested allocation: 320000 Q1: 80000 Q2: 80000 Q3: 80000 Q4: 80000 Justification: The CPU-hours requested is based on the estimates made with NWChem and VASP on Fusion. It shows that NWChem scales well over large number of processors as listed below in comparision to VASP. The test for citral adsorbed on Pt55 cluster with total number of atoms N = 82 has been performed with 32, 64,128 and 256 processors show a substantial increase in performance with the increase in the number of processors up to about 128 processors for NWChem. Scalability of NWChem and VASP on Fusion for supported citral on Pt55 cluster consisting of 82 atoms: Cores Average SCF cycle (s) ---------------------------------------- NWChem VASP ----------------------------------------- 32 9607.47 32.34 64 4839.63 17.27 128 2479.27 11.66 256 1853.55 7.28 Storage requirements: Thank You, The LCRC Accounts System

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[LCRC Accounts] Yearly Allocation Request for SnI4
by accounts＠lcrc.anl.gov 10 Sep '14

10 Sep '14

Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Michael Hu Project Name: SnI4 Division: XSD Project title: Crystalline and amorphous structures of SnI4 Associated funding: DOE and NSERC (Canada) Other Systems: Science: Although pressure-induced amorphization (PIA) has been observed in many solids, the true mechanism is elusive and remain a subject of debate and misinterpretation. Two scenarios have been proposed. In the first observation of this phenomenon in ice Ih , it was assumed the transition is akin to pseudomelting in which the crystalline solid crosses the extrapolated melting line by pressurization at low temperature. This suggests a possible thermodynamic connection between the amorphous state(s) to the liquid, and the prevalent but controversial “two-liquid” model for water is a consequence of this conjecture. Another proposal for PIA transition is that it is a mechanical process due to the instability of the crystal framework under compression and thus violates the Born stability conditions. Recent experiments have shown that in several materials that PIA believed to occur was found to bypass when compression was performed under quasi-hydrostatic conditions. Significantly, archetypal example of ice Ih and SnI4, the subject of our focus, are two solids that no crystalline form was yet to be found in lieu of the disordered structure and the nature of the amorphous phases is still an open question. SnI4 offers several advantages for the characterization of PIA transformation. It is a solid at room temperature and has a fairly high melting point making it comparatively easy to handle as compared to Ice Ih. The 119Sn nuclear resonant inelastic scattering spectra recently measured at sector ID-3, Advanced Phonon Source, Argonne National Laboratory, have revealed very interesting dynamic behavior on pressurization. The objective of the computational investigation is to elucidate the vibrational spectra and to reveal the mechanism of the PIA transformation. Project description: Our preliminary calculations have identified the PIA mechanism as mechanical instability, rather than pseudo-melting. A publication is in preparation. Next we plan to extend simulations to low temperatures, where experimental data were also taken. The aim is to clarify the source of spectrum broadening at room temperature and ambient pressure. Libration is the most likely reason. The objectives of this proposal are (i) to continue the study on the finite temperature effect on the vibration density of states of the Sn atoms in SnI4 and (ii) to start new calculation son the analogous SnBr4 in which experiments have been planned The outline of the research is as follow. The stability of the lattice in the ambient structure will be examined using finite temperature self-consistent lattice dynamics and molecular dynamics calculations. The purpose is to investigate the role of (soft) phonons in the crystal -> crystal transition at ca. 7.2 GPa. Using evolution method, possible candidate structures will be predicted and their properties (i.e. structural and electrical) will be compared with experiment. Constant molecular dynamics calculations will then be performed on prospective phase II structures to examine the mechanism of amorphization. The final goal is to characterize the crystalline structure observed experimentally at 61 GPa. First-principles methods static and dynamic calculations based on density functional approximation will be performed. Specially, structural prediction using evolution algorithms (C. Glass and A. Oganov, J. Chem. Phys. 124, 244704 (2006); Y. Wang, J. Lv, L. Zhu and Y. Ma, Phys. Rev. B 82, 094116 (2010)) and constant pressure molecular dynamics calculations will be performed. The ambient fcc unit cell of SnI4 is consisted of 40 atoms. Any calculations using a supercell model will require exceeding 320 atoms. For this purpose, significant computational resource is required. The density functional codes to be used in this study are well maintained and proven highly-parallel public domain programs. The code Qbox will be used mainly for molecular dynamism calculations. Other codes such as SIESTA and VASP (one of the PI holds the license) will be used for static and properties calculations. Structural search will be performed using our own implementation of the evolution algorithm (Y. Yao, J.S. Tse and K. Tanaka, Phys. Rev. B 77, 052103 (2008)). Structural search and molecular dynamics calculations are computationally (both on the speed of the CPU and memory capacity) very demanding. Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 499999 Q1: 124999 Q2: 125000 Q3: 125000 Q4: 125000 Justification: Storage requirements: Thank You, The LCRC Accounts System

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