Hello, A change in allocation has been requested: Requester: jlow (John J. Low) Project: aimd_catalysis Title: Ab Initio Molecular Dynamics for Catalysis of Biomass to Fuels Description: We will use CPMD to model reactions in aqueous phases. This program has the very efficient Carr-Parinello algorithm for AIMD and several different methods for thermodynamics sampling including metadynamics, umbrella sampling and the Blue-Moon ensemble. CPMD is an excellent tool for modeling reactions in liquids and sampling phase space. The parallel performance of CPMD is fair. The unit cell for our model of glucose in sulfuric acid contains 230 atoms and a unit cell volume of 2500 Å3. The MPI version of CPMD had a parallel efficiency of 70% on 160 processors for this model. The number of planes in the real space grid limits the number of processors which can be used efficiently by CPMD. We plan to implement a hybrid (MPI/OPENMP) version of CPMD of version which should increase the parallel efficiency of CPMD significantly by allowing multiple processors (up to eight on Fusion) to work on each plane of the real space grid and reducing the overhead from MPI All_to_All communication. A metadynamics run of 10ps is adequate to model a step in the glucose decomposition reaction. Ten picoseconds require 7.3 kilocore-hours. We plan to model 20 reaction pathways in the glucose to HMF reaction mechanism. This work will require approximately 150 kilocore-hours. Simulation time of 10ps will be required to sample the phase space of bimetallic metal clusters. We estimate that each of trajectories will require a kilocore-hour. We plan to model the geometry of ten different metal alloy clusters. We will also simulate these clusters with chemisorbed hydrogen and oxygen. This work will require 50 metadynamics runs or 50 kilocore-hours. Current: undetermined amount Justification: Requested: 100000 A specific reason has been given: Additional calculations are required to benchmark AIMD calculation with respect to the G4 calculations of Rajeev and Curtiss This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System