Partial atomic multipoles for internally consistent microelectrostatic calculations

5 years ago

Partial atomic multipoles for internally consistent microelectrostatic calculations

Mateusz Snamina, Piotr Petelenz, Grzegorz Mazur

An extension of the extant microelectrostatic methodologies, based on the concept of distributed generalized polarizability matrix derived from the Coupled Perturbed Hartree–Fock (CPHF) equations, is proposed for self-consistent calculation of charge carrier and charge-transfer (CT) state electrostatic energies in molecular solids, including the doped, defected and disordered ones. The CPHF equations are solved only once and the generalized molecular polarizability they yield enables low cost iterations that mutually adjust the molecular electronic distributions and the local electric field in which the molecules are immersed. The approach offers a precise picture of molecular charge densities, accounting for atomic partial multipoles up to order 2, which allows one to reproduce the recently reported large charge-quadrupole contributions to CT state energies in low-symmetry local environments. It is particularly well suited for repetitive calculations for large clusters (up to 300,000 atoms), and may potentially be useful for describing electrostatic solvent effects. © 2017 Wiley Periodicals, Inc. The electrostatic energies of charge carriers and charge pairs in condensed phase environments of low local symmetry are very sensitive to the detailed shape of molecular electron density. Yet, they may be adequately reproduced when the electron distribution is represented by a set of atomic multipoles up to order 2 (and the corresponding multipolar polarizabilities), provided by ab initio methodology. This enables low cost self-consistent microelectrostatic calculations for large molecular clusters (up to 300,000 atoms).

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/jcc.24903