Granted 150K on Fusion and sent note to PI. - JB On Tue, Aug 4, 2015 at 2:39 PM, [email protected] <[email protected]> wrote:
Hello,
A change in allocation has been requested:
Requester: kclau (Kah Chun Lau) Project: Li-S_Sol Title: Li-S battery Solution 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.
Current: undetermined amount 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.
Requested: 180000
A specific reason has been given: To complete three ongoing Li ion diffusion in three different solvents (~360 atoms equilibrated for another 2 ps) for same solvated Li-salt AIMD calculations (which the total still need 100K core hours). Another 80K core hours are used for Gaussian09 calculations for implicit solvents, thermochemistry calculations for 4 different polysulfides species (~ 40 - 70 atoms) with partial configurations obtained from AIMD trajectories (with total ~ 12 configurations).
This needs to be approved and the final allocation amount decided upon.
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