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From Geometry Optimization to Time Dependent Molecular Structure Modeling: Method Developments, ab initio Theories and Applications

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dc.contributor.advisor Li, Xiaosong en_US Liang, Wenkel en_US 2012-09-13T17:25:49Z 2012-09-13T17:25:49Z 2012-09-13 2012 en_US
dc.identifier.other Liang_washington_0250E_10058.pdf en_US
dc.description Thesis (Ph.D.)--University of Washington, 2012 en_US
dc.description.abstract This dissertation consists of two general parts: I. developments of optimization algorithms (both nuclear and electronic degrees of freedom) for time-independent molecules and II. novel methods, first-principle theories and applications in time dependent molecular structure modeling. In the first part, we discuss in specific two new algorithms for static geometry optimization, the eigenspace update (ESU) method in nonredundant internal coordinate that exhibits an enhanced performace with up to a factor of 3 savings in computational cost for large-sized molecular systems;the Car-Parrinello density matrix search (CP-DMS) method that enables direct minimization of the SCF energy as an effective alternative to conventional diagonalization approach. For the second part, we consider the time dependence and first presents two nonadiabatic dynamic studies that model laser controlled molecular photo-dissociation for qualitative understandings of intense laser-molecule interaction, using {it ab initio} direct Ehrenfest dynamics scheme implemented with real-time time-dependent density functional theory (RT-TDDFT) approach developed in our group. Furthermore, we place our special interest on the nonadiabatic electronic dynamics in the ultrafast time scale, and presents 1) a novel technique that can not only obtain energies but also the electron densities of doubly excited states within a single determinant framework, by combining methods of CP-DMS with RT-TDDFT; 2) a solvated first-principles electronic dynamics method by incorporating the polarizable continuum solvation model (PCM) to RT-TDDFT, which is found to be very effective in describing the dynamical solvation effect in the charge transfer process and yields a consistent absorption spectrum in comparison to the conventional linear response results in solution. 3) applications of the PCM-RT-TDDFT method to study the intramolecular charge-transfer (CT) dynamics in a C<sub>60</sub> derivative. Such work provides insights into the characteristics of ultrafast dynamics in photoexcited fullerene derivatives, and aids in the rational design for pre-dissociative exciton in the intramolecular CT process in organic solar cells. en_US
dc.format.mimetype application/pdf en_US
dc.language.iso en_US en_US
dc.rights Copyright is held by the individual authors. en_US
dc.subject ab initio; density functional theory; electronic structure; geometry optimization; molecular structure; time dependent en_US
dc.subject.other Physical chemistry en_US
dc.subject.other Computer science en_US
dc.subject.other Quantum physics en_US
dc.subject.other Chemistry en_US
dc.title From Geometry Optimization to Time Dependent Molecular Structure Modeling: Method Developments, ab initio Theories and Applications en_US
dc.type Thesis en_US
dc.embargo.terms No embargo en_US

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