Yuriko Aoki, Wataru Mizukami, Ikuko Okawa, Yuuichi Orimoto (Faculty of Engineering Sciences, Kyushu University) Elongation method for efficient quantum chemistry calculations toward functional designs of bio/ nano materials Innovative materials Cost reduction Low environmental load Experiment Theory Programing Explore materials only by experimental alchemists Provide synthesis guidelines Organic ferromagnetic polymers Non - linear optical property (quasi) D system Organic solar battery ※T. Sugawara et al., Internet Electron J. Mol. Des., 2, 112 (2003). We developed the unique theory and method – Elongation method - applicable gigantic bio/nano systems which were impossible to be treated by conventional method. The computational accuracy of elongation method provides high precision, and the computational efficiency is linear scaling. By means of the material designs from a microscopic viewpoint, we aim to contribute our novel approach to green & life innovation, rare metal substitution problems, nanotechnology using IT, and so on. New material design using quantum chemistry & supercomputer Conductivity of nanotubes conductor/semiconductor 0 50000 100000 150000 200000 250000 300000 350000 400000 450000 500000 4 5 6 7 8 9 1011121314151617181920212223242526272829 DNA (B-poly(dA)・poly(dT)) ~O(N 1 ) AO cutoff Starts Our Elongation method (direct calculation) O(N 3~4 ) Number of base pair units (N) Conventional method • Order (N) efficient calculations • Chemical accuracy retained for huge systems Total energy error = 2.59E-09 hartree/atom = 0.0000016 kcal/mol/atom …… Step CPU time (sec) Elongation method By restrained DFT + Elongation method Prediction of J values (Local effective exchange integrals) Frozen -112cm -1 -122cm-1 -112cm -1 -115cm -1 -115cm -1 J 1 J 3 J 5 J 7 J 9 J 2 J 4 J 6 J 8 Br 3 TOT CPU time (sec.) Useful for organic magnets prediction Proteins To calculate electronic states of a gigantic system, the computational time increases with Order N 4 (N:number of atoms). The elongation method developed by our group enables efficient calculations by connecting units successively in a similar way as polymeric polymerization reaction, and calculates only reaction sites considering whole electronic states. The calculation speed is proportional to the linear scaling of the system size (Order N method). Nonetheless, the calculation precision is very accurate with an energy error of 10 -8 Hartree/atom or less compared to the conventional method, and even when considering a gigantic system consisting of 10 5 atoms (for example, chaperone protein…about 120,000 atoms) , those errors can be only within chemical accuracy. Besides, since only the reactive sites are calculated, necessary memory and disk capacity are small, so the system with large size, which could not be treated by conventional method, can be calculated efficiently by elongation method. Any dimension systems can be calculated by thawing the “Frozen region” according to the approaching “Active region” while retaining the concept of one dimensional expansion which calculates only the reactive part. Rare - metal free magnetic polymer design Our original theory & method & applications • Elongation Method • Through space/bond analysis • Organic ferromagnetic analysis • Non - liner optical property analysis • Conductivity analysis • Catalytic reaction analysis Biological molecules Design & prediction of new materials Theoretical Chemistry Frozen Active Reactivate Reactivation Reactivate Refrozen Refrozen Toward exact ab initio computations by Order(N) Ancient chemistry Advanced chemistry System bath Ligand Catalytic reactions ※A. Rajca, J. Wongsriratanakul, S. Rajca, Science, 294, 1503 (2001). Control spin alignment ・・・ one by one activation Effective exchange integrals by Yamaguchi Initiation Propagation Termination Elongation (ELG ) method ・・・・ Computational polymerization Theoretical synthesis of polymers Region localized molecular orbitals (RLMOs) T-C-G-C-T-G-T-A-T-G-T-T-G-A-A-C-C-T-C-T-G-T-C-G-G-C-T-A-G-C Interaction space Frozen Active Starting cluster Attacking monomer Interactive space