Hello, A change in allocation has been requested: Requester: poluektov (Oleg Poluektov) Project: Solar_EPR Title: Solar energy conversion in organic photovoltaics Description: We are evaluating the effect of modifying the polymer portion of the BHJ solar cells to increase the delocalization of the positive polaron, which correlates with solar energy conversion efficiency. Prior work suggested delocalization ranged over multiple subunits; up to 60 Angstroms. 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 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 primary usage of fusion will be in the optimization, frequency calculation, and EPR parameter calculation steps of the work. The optimization subroutines of NWCHEM 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 (using PQS as the optimization engine) for optimization and frequency calculations. The existing allocation is being used to set-up and run optimizations using Density Functional Theory (B3LYP functional and 6-31G basis) using NWCHEM. Calculations for 3 oligomers with an average of six conformations each are in progress. Furthermore, calculations to support a paper on the role of physical deformation of the fullerenes and polymers in the thin film BHJ cells have been submitted. Test calculations on our local systems indicate that the amount of delocalization present is sensitive to the functional present (primarily related to the treatment of correlation effects). We thus anticipate the need to perform calculations with at least three additional functionals for the largest polymers. The EPR parameter calculation (g-tensor and hyperfine calculations) took 1200 CPU hours (using orca 3.0.3). Calculations for 8 new oligomers oligomers with an anticipated six potential conformations for each requiring 9,600 (CPU*oligomer*conformation=200*8*6) for the initial set of calculations, optimizations using alternate functionals and a medium basis set for the largest 3 oligomers will require 7200 cpu hours (400*3*6) and an additional 200,000 (20,000*10*1) CPU hours for the largest 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 288,000 CPU hours. Cons idering that these numbers are for a system slightly smaller in size to those proposed here, 300,000 CPU hours seems to be a reasonable estimate. We did not divide the CPU hours equally as Dr. Mardis is a teaching faculty member and has less research time between October 1-December 31st than she does in the late spring and summer months. Also, the largest optimization/frequency calculations are expected to occur in the second and third quarters. We expect 3 project members (Mardis, Niklas, Poluektov). No non-parallel jobs will be run and all visualization and analysis will be done on local machines. Current: undetermined amount Justification: Requested: 40000 A specific reason has been given: Our original allocation for the Solar_EPR project was small as we hadn't been able to show that we would effectively use the time. We now have a clearer understanding of the computational time and resources needed to succeed with our project. We are requesting additional time as we have used approximately more than half of our CPU in three months and, after a period of testing, we are now running multiple ORCA and NWCHEM calculations. Furthermore, our preliminary calculations revealed that we have a much larger number of energetically accessible conformations than we originally anticipated. Many of these calculations will require the bigmem queue on fusion in order to do the electron paramagnetic resonance (EPR) property calculations for the larger (n=3.5 and above) oligomers. Experimental data is now also available for additional oligomers that we would like to include in our study. This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System