title: Numerical study on the partitioning of the molecular polarizability into fluctuating charge and induced atomic dipole contributions.
abstract: In order to carry out a detailed analysis of the molecular static polarizability, which is the response of the molecule to a uniform external electric field, the molecular polarizability was computed using the finite-difference method for 21 small molecules, using density functional theory. Within nine charge population schemes (Löwdin, Mulliken, Becke, Hirshfeld, CM5, Hirshfeld-I, NPA, CHELPG, MK-ESP) in common use, the charge fluctuation contribution is found to dominate the molecular polarizability, with its ratio ranging from 59.9% with the Hirshfeld or CM5 scheme to 96.2% with the Mulliken scheme. The Hirshfeld-I scheme is also used to compute the other contribution to the molecular polarizability coming from the induced atomic dipoles, and the atomic polarizabilities in eight small molecules and water pentamer are found to be highly anisotropic for most atoms. Overall, the results suggest that (a) more emphasis probably should be placed on the charge fluctuation terms in future polarizable force field development and (b) an anisotropic polarizability might be more suitable than an isotropic one in polarizable force fields based entirely or partially on the induced atomic dipoles.
authors.affiliation: †State Key Laboratory of Precision Spectroscopy, Department of Physics and Institute of Theoretical and Computational Science, East China Normal University, Shanghai 200062, China.|‡NYU-ECNU Center for Computational Chemistry, NYU Shanghai, Shanghai 200062, China.|⊥Laboratory of Computational Biology, National Institutes of Health, National Heart, Lung and Blood Institute, 5635 Fishers Lane, T-900 Suite, Rockville, Maryland 20852, United States.
authors.forename: Ye
authors.initials: Y
authors.lastname: Mei
authors.affiliation: ⊥Laboratory of Computational Biology, National Institutes of Health, National Heart, Lung and Blood Institute, 5635 Fishers Lane, T-900 Suite, Rockville, Maryland 20852, United States.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Simmonett
authors.affiliation: ⊥Laboratory of Computational Biology, National Institutes of Health, National Heart, Lung and Blood Institute, 5635 Fishers Lane, T-900 Suite, Rockville, Maryland 20852, United States.
authors.forename: Frank C
authors.initials: FC
authors.lastname: Pickard
authors.affiliation: §Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
authors.forename: Robert A
authors.initials: RA
authors.lastname: DiStasio
authors.affiliation: ⊥Laboratory of Computational Biology, National Institutes of Health, National Heart, Lung and Blood Institute, 5635 Fishers Lane, T-900 Suite, Rockville, Maryland 20852, United States.
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Brooks
authors.affiliation: ∥Q-Chem Inc., 6601 Owens Drive, Suite 105, Pleasanton, California 94588, United States.
authors.forename: Yihan
authors.initials: Y
authors.lastname: Shao
mesh_terms: D056004:Molecular Dynamics Simulation; D011789:Quantum Theory; D055672:Static Electricity