Calculations of potential energy surfaces: first principles methodology and neural networks

CALCULATIONS OF POTENTIAL ENERGY SURFACES: FIRST PRINCIPLES METHODOLOGIES AND NEURAL NETWORKS Majdi HOCHLAF Université Gustave Eiffel Molecule Host © Potential energy surface Accurate method: CCSD(T)/aug-cc-pVTZ +BSSE+… Larger molecular systems? Need of collision rates with H2instead of He Interplay between computational cost and accuracy Find new alternatives BENCHMARK CALCULATIONS FOR THE GENERATION OF THE PES OF O2+ HE INTERACTING SYSTEMS: 2D-PES OF O2HE RCCSD(T)-F12/aug-cc-pVTZ Groenenboom et al (2000) O He R q O DIFFERENCE Interpolating Moving Least Squares (IMLS) Fit using 8592 points Stationary points of the benzonitrile–He complex 3D-PES. Ab initio vs. MultiLayer Perceptron (MLP) / Deep Neural Network (DNN)/ LSTM Models Cyc-MgC2– H2Cyc-MgC2– He (Lique and co-workers (2025)) Cyc-MgC2– H2(5D-PES) vs. CycMgC2– He (3D-PES) Bounding in Cyc-MgC2: Mg+… C2- 5D-PES of Cyc-MgC2– H23D-PES of Cyc-MgC2– He GM potential depth ~ 533 cm⁻¹ GM potential depth ~ 20 cm⁻¹ Stationary points on the Cyc-MgC2–H25D-PES PES strongly anisotropic From small molecular structures to large and macro molecular structures … Composite scheme: Density functional theory + Corrections is comparable to state-to-art experiments Benchmarking PBE0+D3 and M05-2X+D3 DFTs Strong reduction of computational cost w.r.t. standard post Hartree-Fock approaches ACKNOWLEDGMENTS Tunisia France H2020 EC MultIChem Saudi Arabia THANK YOU FOR YOUR ATTENTION And what else? … M05-2X + D3 M05-2X + D3 CCSD(T)-F12/aVDZ CCSD(T)-F12/aVDZ CCSD(T)-F12/aug-cc-pVTZ CCSD(T)-F12/cc-pVDZ-F12 CCSD(T)-F12/cc-pVTZ-F12 CCSD(T)/CBS HCl-He interaction potential H Cl He R q Long range interactions Ajili Thesis (UPEMLV & F. S. Tunis) After dynamical close coupling computations Low energy de-excitation collision cross sections of HCl by He Again: Strong reduction of electronic structure computational cost with CCSD(T)-F12/aug-cc-pVTZ CONSIDERATION OF INTRA AND INTERMOLECULAR COORDINATES : C3-HE CCSD(T)/aug-ccpVQZ+mid bound function CCSD(T)-F12/augcc-pVTZ