Very short lifetimes of excited states of isolated bases in nucleic acids, on the picosec- ond order, are believed to contribute to photostability of the genetic code. When embedded in DNA this behavior becomes more complex, mainly due to their inter- actions via stacking and hydrogen bonding. The DNA photophysiscs is not fully understood yet. It depends e.g. on the conformation and the character of excited states. The studies on smaller systems can help to improve the understanding of these phenomena. The aim of this work was to examine the dynamics of the excited states of the n → π∗ character of the complex of N-methylformamide dimer and two waters. The study was performed using non-adiabatic dynamics simulations with on-the-fly Surface Hopping algorithm based on the potential energy surfaces and non-adiabatic couplings obtained with multi-reference approach. The results show that after the vertical excitation into delocalized S2 state the system relaxes into S1 state within several tens femtoseconds. For majority of the population, the charac- ter of the state then oscillates between localized and delocalized during the whole course of the dynamics. Comparison with calculations with the waters removed in- dicates that the delocalization is caused by waters serving as a bridge between the two chromophores. 1

We have developed a third-order shear and normal deformable plate/shell theory (TSNDT) incorporating all geometric nonlinearities and used it to analyze, by the finite element method (FEM), transient finite deformations of a sandwich beam with two face sheets and the core made of St. Venant-Kirchhoff materials.  A triangular cohesive zone model with stress based criterion for delamination initiation and energy based relation for complete separation is used to analyze delamination failure in a beam under mixed-mode loading. We have studied transient post-buckling deformations and delamination progression in an axially compressed and initially delaminated clamped-clamped sandwich beam.  The buckling load for transient deformations exceeds that for static deformations and the increase depends upon the loading rate.  This FE software for analyzing deformations of sandwich beam is coupled with that based on the boundary element method (BEM) for studying time-dependent deformations of water and the coupled software is used to analyze deformations of flexible curved hulls due to water slamming loads.  The water is assumed to be inviscid and incompressible and undergo irrotational deformations.  The Laplace equation for the velocity potential is numerically solved by the BEM with normal velocity and pressure assumed to be continuous across the interface between the hull and the water.  Challenging issues resolved in this work include finding the wetted surface of the hull, nonlinear deformations of the fluid due to convective part of acceleration, effects of geometric nonlinearities on hull\'s deformations, resolution of the jet tip, as well as the initiation and propagation of delamination between the face sheets and the core.  It is found that both delamination and geometric nonlinearities significantly affect the hydrodynamic pressure acting on the hull, and transverse shear deformations contribute more to the strain energy absorbed by the core than its transverse normal deformations.  <br />We have used the discontinuous basis functions to derive the Galerkin formulation of a nonlinear problem involving simple shearing deformations of a homogeneous and isotropic thermo-elasto-visco-plastic body with uniform deformations perturbed to simulate the effect of a defect.  The resulting coupled nonlinear ordinary differential equations are integrated with respect to time by using the package, LSODE (Livermore Solver for Ordinary Differential Equations).  Computed results showing localization of deformations into narrow regions are found to agree well with those found by the FEM, and spatial variations of the shear stress are smoother than those obtained by the FEM.<br /><br /> / Ph. D.

A three-level system can be used in a Λ-type configuration in order to construct auniversal set of non-adiabatic quantum gates through the use of non-Abelian non-adiabatic geometrical phases. Such construction allows for high-speed operation times which diminish the effects of decoherence. This might be, however, accompanied by a breakdown of the validity of the rotating wave approximation (RWA) due to the comparable timescale between the counter-rotating terms and the pulse length, which greatly affects the dynamics. Here we investigate the trade-off between dissipative effects and the RWA validity, obtaining the optimal regime for the operation of the holonomic quantum gates.

The surface and interface of the metal nanoclusters and semiconducting nanomaterials play a key role in determining the electronic structure and overall photophysical properties. A single strand DNA stabilizes the metal nanoclusters, but it also influences the structural change, solvation free energy, and photophysical properties. On the other hand, surface and interface states in Pb and Cd chalcogenide nanomaterials affect the phonon mediated hot carrier relaxation. We applied DFT and DFT based non-adiabatic dynamics methods to study the surface and interface?s effects on the photoexcited processes. In the first part, we have studied the Ag nanoclusters' photophysical properties that are affected by the structural isomers, redox potential, nucleobase passivation, and cluster size. Ag nanoclusters are shown alternative reduction potential, which makes nanoclusters of singlet spin multiplicity thermodynamically favorable. Besides, the optically bright transition in the range of 2.5-3.5 eV is shown metal to ligand charge transfer. It is modulated by the s+p+d orbital mixing in the hole and electron states. We also simulate the charge transfer from the photoexcited PbS QD to organic dye (PDI) attached to the QD surface. Depending on the linker group and the dipole moment of neighboring passivating ligands, the PDI-QD conformations are varies. In response to structural change, the total dipole moment is modulated, changing its electronic structure and hence the photoexcited electron transfer rate from the PbS QD to PDI. We also investigate the inorganic-inorganic interactions in the PbCl2 bridged PbSe NPL and PbSe|CdSe Janus heterostructure. The energy dissipation rate of hot electrons is slower in NPL than the hot hole, while hot e-h relaxed to the band-edge by ?1.0ps in the QD. The slower relaxation rate is rationalized by a large average intraband energy difference and smaller coupling term. Besides, the hot carriers in the NPL are spatially separated by ?1.00 ps, which is a favorable condition for the carrier multiplication process. In Janus QD, (100) interfacial layer creates a structural mismatch in the CdSe part. Besides, the energy offset between the valance localized on PbSe and CdSe part is minimum in the PbSe Janus QD of an interface of (111) facet.

The adiabatic or Born-Oppenheimer approximation is often used in molecular calculations to simplify the solution to the Schrodinger equation. The basis of the approximation is the large difference in the relative motions of the nuclei and electrons in the molecule-the electrons are able to respond almost instantly to the movements of the nuclei. Thus, the nuclei may be regarded as being fixed in a certain position and the Schrodinger equation can then be solved using the potential obtained by solving the electronic problem at fixed nuclear configuration. A similar argument can be used to decouple the angular and radial motions of many van der Waals complexes because, like nuclei in molecules, the radial motions in many van der Waals complexes are strongly localized. Fixing the radial separation between the atoms and molecules in the complex to a particular value results in a Schrodinger equation that is much simpler to solve because it is only dependent on angles. van der Waals complexes containing helium atoms, however, present a dilemma because the extremely weak interactions present also lead to large amplitude radial as well as angular motions. Because the basis of the adiabatic approximation is a large difference in time scale between the angular and radial motions, the validity of the adiabatic approximation for helium complexes is uncertain. In this thesis, the adiabatic separation of angular and radial motion is shown to be accurate for extremely floppy complexes of helium by demonstrating its use on the van der Waals molecule He-HCN. A major application of this method is expected to be the quick calculation of approximate wave functions for Diffusion Monte Carlo studies of the rotation of impurity molecules inside ultra-cold droplets of helium. The method presented here is significantly faster than other methods (e.g., Variational Monte Carlo) that have been used to calculate approximate wave functions for Diffusion Monte Carlo.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18494号 / 理博第4009号 / 新制||理||1578(附属図書館) / 31380 / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 中 暢子, 教授 田中 耕一郎, 教授 金光 義彦 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19471号 / 理博第4131号 / 新制||理||1594(附属図書館) / 32507 / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)准教授 竹井 義次, 教授 岡本 久, 教授 小野 薫 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19472号 / 理博第4132号 / 新制||理||1594(附属図書館) / 32508 / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 佐々 真一, 准教授 藤 定義, 准教授 武末 真二 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20892号 / 理博第4344号 / 新制||理||1624(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 高橋 義朗, 教授 川上 則雄, 教授 田中 耕一郎 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

The performances of two D-Wave 2 machines (476 and 496 qubits) and of a 1097-qubit D-Wave 2X were investigated. Each chip has a Chimera interaction graph G. Problem input consists of values for the fields hj and for the two-qubit interactions Ji,j of an Ising spin-glass problem formulated on G. Output is returned in terms of a spin configuration {sj}, with sj = +1 or -1. We generated random spanning trees (RSTs) uniformly distributed over all spanning trees of G. On the 476-qubit D-Wave 2, RSTs were generated on the full chip with Ji,j = -1 and hj = 0 and solved one thousand times. The distribution of solution energies and the average magnetization of each qubit were determined. On both the 476- and 1097-qubit machines, four identical spanning trees were generated on each quadrant of the chip. The statistical independence of the these regions was investigated.