1. FMO-QMC strategy using CASINO Ryo Maezono National Institute for Materials Science, Tsukuba, Japan. MAEZONO.Ryo@nims.go.jp (Fragment Molecular Orbital method) CASINO workshop@Towler Institute, Tuscany, Italy.

2. FMO イントロ (1) Very interesting target for precise QMC… Huge molecules… - The whole molecule is too huge… Generating the whole trial nodes is difficult… - Quantum dynamics is believed to be important only within each fragment. For distant fragments, the interaction is well described by classic electrostatic fields, as believed. ‘Fr1’ ‘Fr2’ ‘Fr3’

3. FMO とは the whole molecule calculation What is FMO? Approximation; Now implemented in ‘GAMESS’ and ‘ABINIT_MP’, ‘NWChem’ ‘Fr1’ ‘Fr2’ ‘Fr3’ ‘Glycine_trimer’ into calculations on each fragment. Dividing (Fragment Molecular Orbital method)

4. FMO 近似 FMO approximation Interactions only between adjacent fragments is taken into account. I II … III IV -Two fragments example; -Multi fragments extension; ; ; ( )

5. 計算手順 (1) Procedure… by ‘GAMESS’ or ‘ABINIT_MP’ -Similar procedure on QMC… -FMO-SCF; Iterations to reach convergence… ; Cusp_corr., Jastrow, DMC, … More correlations!

6. 計算手順 (2) Procedure… by ‘GAMESS’ or ‘ABINIT_MP’ -Similar procedure on QMC… ; Cusp_corr., Jastrow, DMC, … - More correlations! - No huge gwfn.data is required! based on partial gwfn.data for each fragment… by ‘GAMESS’ or ‘ABINIT_MP’

7. 将来構想 Future perspective… Accurate treatment of ‘reaction centre’ without annoying huge whole size… - MP2, MP4 etc… - QMC… (e.g., DNA stacking…) vdW force - FMO ‘Engine’ ‘Framework’

8. 最初の構想 As a kick-off work… - HFVMC (VMC w/o Jastrow) FMO approx. is reasonable at the level of QMC?? ?? (@ MP2 they confirmed.) ‘Fr1’ ‘Fr2’ ‘Fr3’ Full Whole QMC is feasible. - VMC with Jastrow. - DMC - FMO-SCF (ABINIT_MP or GAMESS). FMO; -687.387353735997 Full; -687.3875159324

9. 實装の試行 Trial implementation… - by FMO-SCF Code extension to include as ‘mol_density.fmo’ input, gwfn.data mol_density.fmo, gwfn.fmo - Ion positions of other fragments. - Charge densities of other fragments accumulated (by ‘ABINIT_MP’) on each cells. - by FMO-SCF as ‘gwfn.fmo’

10. HFVMC の結果 Result at HFVMC… HFVMC ABINIT_MP fr1 -122.86(7) -122.7992645203 0 fr2 -307.8(1) -307.6073508713 - fr3 -683.5(2) -683.4622078107 0 fp12 -518.4(4) -518.311823403056 0 fp13 -885.1(1) -885.152669732591 0 fp23 -1219.5(2) -1218.91371271375 - FMO-SCF ; -687.387353735997 Full-SCF ; -687.3875159324 FMO-HFVMC ; -687.8(6) Full-HFVMC ; -686.9(9) N.B., No cusp corrections. - Large amount of accumulation, - careful choice of ‘NVMCAVE’ - ‘Core stacking’ --> lower estimation (*Andrea’s paper)

11. 技術的事項 Technical issues… - Cusp corrections: ‘Floating gaussian centre’ is used… - Filters: {gwfn.data_fr_j} ‘ABINIT_MP’ etc. {density.data_fr_j} ‘CASINO’ code extension by Mike. (trial by RM) - Code extensions: - Calculation including electro-static field from other fragments.

12. まとめ ○ FMO-SCF --> FMO-QMC enables us… Summary… without treating huge trial wavefunctions. to concentrate only on the active site ○ On-going work… where precise handling of electronic correlation is required. - VMC --> DMC ○ Future… - DNA stacking, Biological reactions etc. where the correlation expected to be important… …for increasing system size MP 2 QM C