@unpublished{pittir8494,
           month = {September},
           title = {Accurate Polarization Energies from Force Fields},
          author = {Dongliang Yang},
            year = {2010},
        keywords = {DPP2; quadrupole-quadrupole polarizability; water; distributed polarizabilities; single center expansion; multivariant regression},
             url = {http://d-scholarship-dev.library.pitt.edu/8494/},
        abstract = {The distributed point polarizable water model (DPP2) [Ref 1] which was recently developed in our group, has explicit terms for induction, charge penetration, and charge transfer. It is a refinement of the DPP model [Ref 2] which was also developed in our group. The DPP2 model has been found to accurately describe the interaction energy in water clusters. In this work, we aim to further improve the accuracy of DPP2 in calculating the induction energy. There are two ways to model higher-order polarization effects, one is through distributed atomic dipole polarizabilities, the other is through single-center expansion with higher multipoles. We developed a fitting method which can map the distributed dipole polarizabilities into the dipole-dipole ({\ensuremath{\alpha}}), dipole-quadrupole (A) and quadrupole-quadruple (C) polarizabilities. DPP2 uses three distributed atomic polarizabilities? {\ensuremath{\alpha}}?\_O,{\ensuremath{\alpha}}\_H1,{\ensuremath{\alpha}}\_H2 which are located on oxygen and hydrogen atoms to describe induction effects. We show that the A and C values associated with the DPP2 model differ appreciably from the results of high level ab-inito methods [Ref 3, 4, 5, 25]. We have explored several strategies for improving on the DPP2 results. We describe a 4-site polarizable model, in which we split the polarizability of oxygen onto its two lone-pair sites, and which gives results in good agreement with the ab-initio calculations.}
}