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SYQM: Symposium Precise Quantum Molecules
SYQM 1: Precise Quantum Molecules
SYQM 1.2: Hauptvortrag
Donnerstag, 11. September 2025, 11:15–11:45, ZHG105
Accurate calculation of non-covalent interactions using explicitly correlated local correlation methods — •Hans-Joachim Werner1, Andreas Hansen2, and Peter J. Knowles3 — 1Institut für Theoretische Chemie, Universität Stuttgart, Germany — 2Mulliken Center for Theoretical Chemistry, Universität Bonn, Germany — 3School of Chemistry, Cardiff University, Cardiff CF10 3AT, U.K.
Recent developments of highly accurate electron correlation methods applicable to large molecular systems are reviewed. This includes local correlation approximations, explicit correlation methods, as well as fragmentation or embedding approximations. Using a combination of these approaches it has become possible to predict reaction energies, isomerization energies, conformational energies, and intermolecular interaction energies for systems with over hundred atoms with sub-kcal/mol accuracy. In this talk we present recent benchmark calculations [1] for non-covalent interactions (NCI) in large π-stacked molecular aggregates and host-guest systems using the PNO-LCCSD(T)-F12 method as implemented in Molpro. Key NCI systems previously evaluated using FN-DMC and other LCCSD(T) methods are reexamined with focus on the question whether CCSD(T) overbinds in large π-stacked complexes or other systems with high polarizability.
[1] A. Hansen, P. J. Knowles, and H.-J. Werner, J. Phys. Chem. A (2025), https://doi.org/10.1021/acs.jpca.5c02316
Keywords: Quantum chemistry; local correlation methods; explicitly correlated methods; reaction energies; intermolecular interactions