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Hi there! Welcome to my research blog.

Extension and Evaluation of the D4 London Dispersion Model for Periodic Systems

Authors Eike Caldeweyher Jan-Michael Mewes Sebastian Ehlert Stefan Grimme Abstract We present an extension of the DFT-D4 model [J. Chem. Phys., 2019, 150, 154122] for periodic systems. The main new ingredients are additional reference polarizabilities for highly-coordinated group 1-5 elements derived from periodic electrostatically-embedded cluster calculations. To illustrate the performance of the updated method, several test cases are considered, for which we compare D4 results to those of its predecessor D3(BJ) as well as to a comprehensive set of other dispersion-corrected methods.

Understanding and Quantifying London Dispersion Effects in Organometallic Complexes

Authors Markus Bursch Eike Caldeweyher Andreas Hansen Hagen Neugebauer Sebastian Ehlert Stefan Grimme Abstract Quantum chemical methods are nowadays able to determine properties of larger chemical systems with high accuracy and Kohn-Sham density functional theory (DFT) in particular has proven to be robust and suitable for everyday applications of electronic structure theory. A clear disadvantage of many established standard density functional approximations like B3LYP is their inability to describe long-range electron correlation effects.

Simplified DFT methods for consistent structures and energies of large systems

Authors Eike Caldeweyher Jan Gerit Brandenburg Abstract Kohn-Sham density functional theory (DFT) is routinely used for the fast electronic structure computation of large systems and will most likely continue to be the method of choice for the generation of reliable geometries in the foreseeable future. Here, we present a hierarchy of simplified DFT methods designed for consistent structures and non-covalent interactions of large systems with particular focus on molecular crystals.

Extension of the D3 dispersion coefficient model

Authors Eike Caldeweyher Christoph Bannwarth Stefan Grimme Abstract A new model, termed D4, for the efficient computation of molecular dipole-dipole dispersion coefficients is presented. As in the related, well established D3 scheme, these are obtained as a sum of atom-in-molecule dispersion coefficients over atom pairs. Both models make use of dynamic polarizabilities obtained from first-principles time-dependent density functional theory calculations for atoms in different chemical environments employing fractional atomic coordination numbers for interpolation.

A general intermolecular force field based on tight-binding quantum chemical calculations

Authors Stefan Grimme Christoph Bannwarth Eike Caldeweyher Abstract A black-box type procedure is presented for the generation of a molecule-specific, intermolecular potential energy function. The method uses quantum chemical (QC) information from our recently published extended tight-binding semi-empirical scheme (GFN-xTB) and can treat non-covalently bound complexes and aggregates with almost arbitrary chemical structure. The necessary QC information consists of the equilibrium structure, Mulliken atomic charges, charge centers of localized molecular orbitals, and also of frontier orbitals and orbital energies.

London Dispersion Enables the Shortest Intermolecular Hydrocarbon H•••H Contact

Authors Sören Rösel Henrik Quanz Christian Logemann Jonathan Becker Estelle Mossou Laura Canãdillas-Delgado Eike Caldeweyher Stefan Grimme Peter R. Schreiner Abstract Neutron diffraction of tri(3,5-tert-butylphenyl)-methane at 20 K reveals an intermolecular C–H···H–C distance of only 1.566(5) Å, which is the shortest reported to date. The compound crystallizes as a C3-symmetric dimer in an unusual head-to-head fashion. Quantum chemical computations of the solid state at the HSE-3c level of theory reproduce the structure and the close contact very well (1.