DFT-derived atomic multipoles in AMOEBA force field for calculating intermolecular interactions of azabenzenes dimers

Abstract

Abstract The understanding of intermolecular interactions holds the key for many applications of organic semiconductor materials, such as azabenzenes, since they govern molecular configurations and the electron transfer rate. While the high-level quantum mechanics (QM) method can supply accurate interaction energies, it is most often time-consuming, which limits its large-scale applications. To address this issue, the approach using the polarizable force field (e.g. AMOEBA) has been recently developed. The quality of the polarizable force field is largely determined by its anisotropic atomic multipole potential (AMP). In this paper, AMPs of azabenzenes are first derived by fitting the QM-based electrostatic potentials using various exchange–correlation functionals of the density functional theory (DFT). The performance of the derived AMPs on the computations of the intermolecular interactions between azabenzenes is systematically evaluated. The findings of this study demonstrate that the both DFT-derived and MP2-derived AMPs can reproduce intermolecular electrostatic interactions in terms of that from the golden standard CCSD(T)/CBS computations. Our findings, therefore, demonstrate the feasibility to use relatively cheap QM method to derive AMPs for azabenzenes.