Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: John J. Low Project Name: metadissolve Division: CLS Project title: Ab Initio Molecular Dynamics Simulations of Aqueous Reactions of AluminoSilicates Associated funding: Other Systems: Science: The reactions of Aluminosilicates in water are important in nuclear waste storage, zeolite synthesis, hydrothermal stability and mineralogy. These reactions involve changes in the coordination of reactants and products which can be difficult to model with continuum models of solvents often exploited in ab initio simulations of these reactions. We propose to model the kinetics of the polymerization reactions of aluminosilicates in solution and on surface of amorphous aluminosilicates. This study will establish the utility of advanced molecular dynamics with a explicit solvent models over implicit solvent models. Project description: The project will predict the rates of aqueous polymerization reactions of aluminosilicates with ab initio molecular dynamics. We will generate free energy surfaces for dimerization reactions of SiOH4 + SiOH4, Al(OH)3 + SiOH4 and B(OH3) + SiOH4 in water and vacuum. Each of these reactions will carried in pH neutral, acidic (1M HCl) and basic (1M NaOH) solutions to model the effect of pH on these reactions. We will use metadynamics to define the reaction coordinate and estimates of free energies. Umbrella sampling will be use to predict accurate free energies and estimates of rates. CPMD (http://www.cpmd.org), PLUMED (http://www.plumed-code.org) and WHAM (http://membrane.urmc.rochester.edu/content/wham) will be used in this project. CPMD is a plane-wave pseudopotential code which exploits Carr-Parrinello Molecular Dynamics. CPMD is very efficient method for ab initio molecular dynamics. PLUMED is an open source plugin, which works together with CPMD, for free energy calculations in molecular systems. Although CPMD can do metadynamics, PLUMED implements the reaction path collective variable (RPCV). The RPCV should increase the efficiency of metadynamics and umbrella sampling. WHAM is a program which performs a weighted histogram analysis of the trajectory from umbrella sampling to generate the free energy changes along the reaction coordinate. CPMD is a highly scalable parallel code. The hybrid MPI/openMP Version of CPMD 3.15.3 scales very well. CPMD can use 560 cores on either blues or fusion very efficiently for these models considered in this project. Additional scaling can be obtained with multiple walkers and task groups, which is available in CPMD. This will enable additional levels of parallelism could scale efficiently to thousands of cores. PLUMED implements a reaction path collective variable will allow us to simulate this reaction with one dimensional metadynamics. One dimensional metadynamics is at least two to three times more efficient than two or three dimensional sampling. PLUMED will increase the efficiency of our metadynamics and umbrella sampling by a factor of two to three. Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 200000 Q1: 100000 Q2: 100000 Q3: 0 Q4: 0 Justification: Storage requirements: Thank You, The LCRC Accounts System