Atomic multipolar contributions to electronic polarization in organic molecular crystals

Department of Chemistry, Princeton University - Princeton, NJ 08540, USA

Received: 5 August 2002
Accepted: 18 September 2002

Abstract

The self-consistent computation of electronic polarization in organic molecular crystals is extended to include, in first order, corrections in the continuous gas-phase charge distribution . The potential at molecule a in the crystal is due to the difference between and a point-charge approximation. , which represents atomic multipolar contributions, is evaluated for crystals of anthracene and perylenetetracarboxylic dianhydride (PTCDA). The corrections to the polarization energies of molecular cations are and -0.14 for anthracene and PTCDA, respectively, while and 0.18 for the anions. The leading term of atomic multipoles is the -charge interaction that corresponds to the charge-quadrupole term in the submolecular approach. There are also new contributions in -redistributed charge and coupling of induced dipoles to gradients of . First-order correction to electronic polarization is a general approach that combines the advantages of discrete charges for self-consistent treatment of crystals with accurate electrostatic potentials based on the best available molecular charge distribution.