The solvation structure of CO2 in dichloromethane-A comparative correlated, semi-empirical and classical MD simulation study

In this work the structural and dynamical properties of CO2 in dichloromethane were studied via classical and QMCF MD simulations employing a variety of increasingly complex computational methods, namely correlated resolution-of-identity second-order Moller-Plesset perturbation theory (RI MP2), resolution -of-identity density functional theory (DFT) using the B3LYP functional with and without dispersion cor-rection, semi-empirical self consistent density-functional tight-binding (SCC DFTB) as well as the second -generation geometries, vibrational frequencies, and non-covalent interaction extended tight-binding (GFN2-xTB) approach. All levels of theory yield a similar description of the spherically-shaped first sol-vation layer found in the range of 6.4 to 6.9 A. The structural and dynamical data obtained via RI B3LYP-D3 are found in good agreement with the high level RI MP2 reference, whereas the SCC DFTB/3ob and GFN2-xTB methods displayed minor deficiencies in the description of halogen-based inter-actions. Despite the observed structural differences both the vibrational frequencies of the solute as well as the first shell mean ligand residence times show similar values, pointing towards rapid exchange reac-tions of first shell ligands with the bulk. In addition several classical potential models for the description of the system have been assessed and adjusted MM potential parameters providing structural and dynamical data comparable to the much more expensive quantum chemical methods are provided.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).