Dresden 2026 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 51: Correlated Electrons: Method Development II

TT 51.3: Talk

Wednesday, March 11, 2026, 15:30–15:45, HSZ/0101

Understanding discrepancies in noncovalent interaction energies from wavefunction theories for large molecules — •Andreas Irmler, Tobias Schaefer, Alejandro Gallo, and Andreas Grueneis — TU Wien, Vienna, Austria

Recent advances in combining quantum-mechanical methods with machine learning have generated excitement for large-scale molecular simulations. Yet the reliability of these approaches depends on the benchmark accuracy expected from high-level quantum reference methods. Discrepancies have been reported between two widely trusted references - diffusion quantum Monte Carlo and coupled-cluster theory - for large noncovalent complexes, posing a puzzle for the accuracy required to support QM/ML modeling. In this talk, I analyze these discrepancies, identify their origin, and present modifications to the coupled-cluster ansatz that restore reliable, high-accuracy interaction energies for molecules on the hundred-atom scale, paving the way toward more accurate predictive simulations.

Keywords: coupled-cluster methods; electronic structure theory; non-covalent interactions; Quantum mechanics