Authors Sebastian Spicher Eike Caldeweyher Andreas Hansen Stefan Grimme Abstract The strongly attractive noncovalent interactions of charged atoms or molecules with π-systems are important binding motifs in many chemical and biological systems. These so-called ion–π interactions play a major role in enzymes, molecular recognition, and for the structure of proteins. In this work, a molecular test set termed IONPI19 is compiled for inter- and intramolecular ion–π interactions, which is well balanced between anionic and cationic systems.

Authors Eike Caldeweyher Abstract Machine learning (ML) has recently become very popular within pharmaceutical industry. Especially tasks as, e.g., building predictive models, performing virtual screening, or predicting compound activities are great usecases for potential ML applications. Traditional ML models often rely on the quantitative structure-activity relationship (QSAR) that has been popularized by medicinal chemists and statisticians to relate bioactivities to specific functional group manipulations. This QSAR approach decreases the dimensionality of the underlying problem and projects the molecular structure into a space spanned by the physicochemical features.

Authors Christoph Bannwarth Eike Caldeweyher Sebastian Ehlert Andreas Hansen Philipp Pracht Jakob Seibert Sebastian Spicher Stefan Grimme Abstract This review covers a family of atomistic, mostly quantum chemistry (QC) based semiempirical methods for the fast and reasonably accurate description of large molecules in gas and condensed phase. The theory is derived from a density functional (DFT) perturbation expansion of the electron density in fluctuation terms to various orders similar to the original density functional tight binding model.

Authors Eike Caldeweyher Abstract Mean-field electronic structure methods like Hartree–Fock (HF) or Kohn–Sham (KS) Density Functional Theory (DFT) do not account for long-range correlation effects and consequently not for London Dispersion (LD). These LD forces contribute significantly to the interaction between molecular aggregates and are thus mandatory for a quantitative comparison of in silico predictions with experimental observations. Casimir and Polder formulated long-range correlation in terms of dynamic polarizabilities and established the foundation of all LD corrections within a DFT framework.

Authors Philipp Pracht Eike Caldeweyher Sebastian Ehlert Stefan Grimme Abstract We propose a semiempirical quantum chemical method, designed for the fast calculation of molecular Geometries, vibrational Frequencies and Non-covalent interaction energies (GFN) of systems with up to a few thousand atoms. Like its predecessors GFN-xTB and GFN2-xTB, the new method termed GFN0-xTB is parameterized for all elements up to radon (Z = 86) and mostly shares well-known density functional tight-binding approximations as well as basis set and integral approximations.

Authors Eike Caldeweyher Sebastian Ehlert Andreas Hansen Hagen Neugebauer Sebastian Spicher Christoph Bannwarth Stefan Grimme Abstract The so-called D4 model is presented for the accurate computation of London dispersion interactions in density functional theory approximations (DFT-D4) and generally for atomistic modeling methods. In this successor to the DFT-D3 model, the atomic coordination-dependent dipole polarizabilities are scaled based on atomic partial charges which can be taken from various sources. For this purpose, a new charge-dependent parameter-economic scaling function is designed.