All, I had to enter this one manually since Oleg couldn't get the project site to accept his request so I added it in myself. We'll continue debugging the issue once Ti returns from vacation. ========== A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: Oleg Poluektov Applicant's institution: ANL Applicant's division: CSE Project Name: Solar_EPR Project title: Solar energy conversion in organic photovoltaics Associated funding: DOE Division of Chemical Sciences, Geosciences, and Biosciences Other Systems: Science: This work is focused on the elucidating the electronic structures of donor-acceptor polymers which are the most promising solar conversion material for organic photovoltaic devices. A key process of the solar energy conversion in organic photovoltaics is the initial charge separation. Stronger delocalization of the positive polaron on the polymer minimizes wasteful charge recombination. The delocalization correlates with solar energy conversion efficiency and is determined by the electronic structures of the organic molecules. The first aim is to use Density Functional Theory (DFT) to evaluate the extent of polaron delocalization on these donor-acceptor polymers. The second aim is to explore the effect of solvent and conformation on the calculated magnetic resonance parameters in order to assess the feasibility of this approach for modeling the bulk polymers. These results will facilitate interpretation of our multifrequency Electron Paramagnetic Resonance (EPR) data of polymer fullerene bulk heterojunction (BHJ) solar cells. This study will provide a rationale for design of efficient BHJ blends. Project description: We are evaluating the effect of modifying the polymer portion of the BHJ solarcells to increase the delocalization of positive polaron, which correlates with solar energy conversion efficiency. Prior work suggested delocalization ranged over multiple subunits; up to 60 A. However, due to our existing computational power we were not able to assess larger structures. Furthermore, test calculations indicated sensitivity to both conformation and external charges. The current work seeks to investigate a series of recently synthesized polymers and to include longer oligomers to test the limits of the delocalization.We intend to run a series of gas-phase model DFT optimizations to determine the low energy polymer conformations using standard ab initio optimization codes such as Gaussian09, GAMESS, or NWCHEM. This will also allow us to generate a set of conformers likely to be present in the experimental samples. The resultant conformations will be used to calculate EPR parameters (g-tensors and hyperfine coupling constants) using Orca 3.0.3. Oligomers of varying length will be investigated to evaluate delocalization ranges and sensitivity of electronic structure parameters to oligomer length. The initial structure building, monomer and dimer test calculations, and analysis of spin densities will be carried out on our lab computers. The optimization subroutines of NWCHEM, Gaussian09, and GAMESS are highly parallelized. Orca 3.0.3 is a highly accurate program for calculating EPR parameters. It has recently been installed on fusion. Benchmarks on a small local workstation with Orca showed good scaling up to 16 processors for the EPR parameter subroutines. Test calculations performed on this small workstation for the largest oligomer we calculated so far took about 200 (small basis set) to 20,000 (large basis set) CPU hours for optimization and frequency calculations. The EPR parameter calculation (g-tensor and hyperfine calculations) took 1200 CPU hours. Calculations for 10 oligomers with an anticipated six potential conformations for each requiring 12,000 (200*10*6) for the initial set of calculations and an additional 200,000 CPU hours for the larger basis set calculation for the lowest energy conformation of each oligomer. The EPR parameter calculations will take 72,000 (1200*10*6) CPU hours. This totals to 284,000 CPU hours. Considering that these numbers are for a system slightly smaller in size to those proposed here, 400,000 CPU hours seems to be a reasonable estimate. Industry partnership: Project URL: Requested allocation: 400,000 Q1: 0 Q2: 0 Q3: 0 Q4: 400,000 Justification: Storage requirements: 1TB The requester has used undetermined amount hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System