Comparison of Polarization Energies from B3LYP and MP2 Parameterizations: Spherical Benzene and Anthracene Clusters

To characterize polarization energies of organic small molecule based materials induced by aggregation, electronic structure calculations including density function theory (DFT) method become intractable when the size of the aggregates increases. A practical solution is to develop force field based on electronic structure calculations and molecular dynamics simulations. In this work, we performed B3LYP and MP2 calculations of neutral, cationic, and anionic benzene and anthracene and used these results to derive the state specific atomic polarizabilities (SSAPs) then to calculate the atomic dipole moments using QTAIM for better parameterization of the isotropic atomic polarizability for ionic systems. Ren’s atomic multipole parameterization method was also compared to a less computationally intensive B3LYP result and a grid quadrature method for multipole analysis in GDMA. Our results show that the trend in cluster size is the same for both parameterization methods, however, the magnitude of the apparent polarization energy is different for the bulk with a negatively charged carrier. B3LYP produces results closer to the experimental values for the positively charged carrier. The intramolecular electrostatic interactions of the negative charge carrier are a major depolarizing force. This relationship is reversed in the positive charge carrier.