Hello, A change in allocation has been requested: Requester: zapol (Peter Zapol) Project: AlN Title: A DFT study of reaction pathways of NH3 decomposition on AlN (0001) surface Description: Structure optimizations of the adsorbate-free (0001) surface of AlN were already investigated using (2 × 2) surface unit cells. We will perform density functional theory (DFT) calculations to determine structure, bonding, and reaction energies of the adsorbed species. 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 Climbing Nudged Elastic Band (cNEB) method of Henkelman and coworkers will be used to calculate transition states and activation barriers for formation of different surface species. Each structure in the supported (0001) surface of AlN typically involves ~100 atoms. To obtain accurate reaction energies and barriers, rigorous density functional theory (DFT) calculations are needed. We intend to carry out the DFT calculations using the VASP package. VASP is currently available on Blues cluster and scaling with number of processors is well established. For the MPI version of VASP with the system size of ~100 atoms, a good performance was observed up to 32 processors. Energy optimization in VASP takes approximately 750 CPU hours and we plan approximately 100 of such calculations for different adsorbate geometries. The Climbing Nudged Elastic Band (cNEB) calculation (with 5 to 7 images) takes approximately 1600 CPU hours and we plan to run 60 of these calculations to find reaction pathways. So our total request is 750*150 + 60*1600 = 208,500 core hours Current: undetermined amount Justification: Requested: 50000 A specific reason has been given: we have received considerably smaller amount than requested and as a result we have a negative balance. Please add time or at least advance the remaining balance in order to continue the project. This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System