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MO: Fachverband Molekülphysik

MO 7: Machine Learning and Computational and Theoretical Molecular Physics

MO 7.5: Talk

Wednesday, March 8, 2023, 12:15–12:30, F142

The performance of CCSD(T) for the calculation of dipole moments in diatomics — •Xiangyue Liu¹, Laura McKemmish², and Jesús Pérez-Ríos³ — ¹Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany — ²School of Chemistry, UNSW Sydney, Sydney, NSW 2052, Australia — ³Department of Physics and Astronomy, Stony Brook University, Stony Brook 11794, New York, USA

Electric dipole moment plays an important role in understanding intermolecular interactions. High-quality electric dipole moments are essential for accurate predictions of vibrational and rotational spectroscopy. In this work, the performance of CCSD(T) (coupled cluster with single, double, and perturbative triple excitations) has been evaluated with accurate experimental data of diatomic molecules. In particular, CCSD(T) accuracy for the equilibrium bond length, vibrational frequency, and dipole moments has been discussed. We find that CCSD(T) gives accurate predictions on dipole moments for most of the molecules in the test set. However, disagreements have been found for a few molecules, which can hardly be explained by relativistic or multi-reference effects. The impacts of basis set family and size have also been discussed.