eprintid: 8494 rev_number: 5 userid: 6 dir: disk0/00/00/84/94 datestamp: 2011-11-10 19:52:42 lastmod: 2016-11-15 13:46:26 status_changed: 2011-11-10 19:52:42 type: thesis_degree metadata_visibility: show contact_email: yangdd916@gmail.com item_issues_count: 0 eprint_status: archive creators_name: Yang, Dongliang creators_email: yangdd916@gmail.com title: Accurate Polarization Energies from Force Fields ispublished: unpub divisions: sch_as_chemistry full_text_status: public keywords: DPP2; quadrupole-quadrupole polarizability; water; distributed polarizabilities; single center expansion; multivariant regression 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 (α), dipole-quadrupole (A) and quadrupole-quadruple (C) polarizabilities. DPP2 uses three distributed atomic polarizabilities〖 α〗_O,α_H1,α_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. date: 2010-09-20 date_type: completed institution: University of Pittsburgh refereed: TRUE etdcommittee_type: committee_chair etdcommittee_type: committee_member etdcommittee_type: committee_member etdcommittee_name: Jordan, Kenneth etdcommittee_name: Hutchison, Geoffrey etdcommittee_name: Coalson, Rob etdcommittee_email: jordan@pitt.edu etdcommittee_email: geoffh@pitt.edu etdcommittee_email: coalson@pitt.edu etdcommittee_id: JORDAN etdcommittee_id: GEOFFH etdcommittee_id: COALSON etd_defense_date: 2010-08-06 etd_approval_date: 2010-09-20 etd_submission_date: 2010-07-21 etd_access_restriction: immediate etd_patent_pending: FALSE assigned_doi: doi:10.5195/pitt.etd.2011.8494 thesis_type: thesis degree: MS committee: Kenneth Jordan (jordan@pitt.edu) - Committee Chair committee: Geoffrey Hutchison (geoffh@pitt.edu) - Committee Member committee: Rob Coalson (coalson@pitt.edu) - Committee Member etdurn: etd-07212010-184327 other_id: http://etd.library.pitt.edu/ETD/available/etd-07212010-184327/ other_id: etd-07212010-184327 citation: Yang, Dongliang (2010) Accurate Polarization Energies from Force Fields. Master's Thesis, University of Pittsburgh. (Unpublished) document_url: http://d-scholarship-dev.library.pitt.edu/8494/1/Dongliang_Yang08062010F5.pdf