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Showing 1 to 18 of 18 for “"Multi Reference"”.
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Large-Scale Applications of Multi-Reference Methods in Chemistry and Development of a Multi-Reference Moller-Plesset Perturbation Theory Program
… electronic structures require the application of multi-reference methods. The anti-tumor efficacy of the natural product Neocarzinostatin is based on the formation of diradicals and causes DNA cleavage and finally cytolysis. Computations on model systems performed in the present work show the …
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Multi-Reference Pseudo-Random Phase-Encoded Joint Transfrom Correlation
… the superiority of using a phase SLM only in a multi-reference phase encoded joint transform correlator(JTC) compared to an ordinary JTC. Maximal length sequences are shifted to form two dimensional orthogonal arrays referred as m-arrays. The phase mask is used in one step to encode multiple …
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Ab Initio Treatment of Complex Systems Kohn-Sham Orbitals for Multi Reference Methods and the Base Pairing Properties of Xanthine
… untersucht die Eignung von LHF-Orbitalen für Multireferenzverfahren. Das Ziel dieses Teils ist eine effizientere Berechnung angeregter Zustände, was zur spektroskopischen Charakterisierung vieler organischer und bioorganischer Moleküle wichtig ist. Der zweite Teil befasst sich mit …
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Machine Learning Coupled Potential Energy Surfaces
… approach is first validated at the ab initio multi-reference configuration interaction (MRCI) level of theory for various molecules. We examine the ability of the proposed model to accurately reproduce energies near a minimum energy conical intersection (MECI) and analyze its performance in …
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Theoretical investigations of the electronic processes in organic photovoltaics
… and by using the [delta]SCF wavefunctions for a multi-reference basis we construct a new perturb then diagonalize multi-reference perturbation theory method that performs well for both ground and excited state potential energy surfaces, called [delta]SCF(2). Our computed singlet fission rates are …
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Statistical estimation in the presence of group actions
… shifted by an unknown offset (this is "multi-reference alignment"). Or imagine we want to reconstruct an unknown 3D structure (e.g. a molecule) given many noisy pictures of it taken from different unknown angles (this is "cryo-EM"). These problems (and many others) involve the action of …
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Quantenchemische Studien zu ausgewählten Themen der Biochemie
… Konstanten bestimmt. Zum Einsatz kamen die multi reference CI und die coupled cluster Methoden. Wenn möglich, wurde ein Vergleich zu experimentellen Daten gezogen. Während die berechneten Größen für das neutrale Selensulfid eine gute Übereinstimmung mit den experimentellen Daten zeigten, …
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Development and Efficient Implementation of Electron-Hole Interaction Kernel for Investigation of Electronic Excitations in Semiconductor and Metallic Nanoparticles
… in metallic nanoparticles, resulting in a cheap multi-reference approach to obtaining electron-correlation. Finally, the moment generated molecular orbital basis is derived to provide an alternative approach that utilizes moments of the reference function to decouple particle and hole states. A …
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Vibrational Spectroscopy and Potential Energy Surface Analysis of the X˜ And B˜ States of Thiophosgene
… A1) levels up to 8,000 cm-1. A six-dimensional multi-reference PES has also been fit, to a series of CASSCF ab initio calculations modeling the B˜(1 A1) state. Wavefunctions for both the X˜ (1A1) and B˜ (1A1) states were calculated in harmonic oscillator bases using the same …
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A multireference coupled-cluster method using a single-reference formalism.
… to the stretching of a chemical bond. A multi-reference coupled-cluster singles and doubles (MRCCSD) method utilizing two reference determinants, which differ by a two electron excitation, is then proposed. One of these determinants is selected as the formal reference determinant. The …
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High-accuracy electronic structure quantum Monte Carlo for molecular systems
… high accuracy calculations which have involved multi-reference wave functions, extensive variational optimizations, and the use of massively parallel platforms demonstrate clearly the unique capabilities of the QMC approach.
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Dynamic Testing of In-Situ Composite Floors and Evaluation of Vibration Serviceability Using the Finite Element Method
… testing of three bare (non-fit out) in-situ multi-bay steel composite floors to estimate their dynamic parameters/response and to identify trends in dynamic behavior, and development of a set of fundamental finite element (FE) modeling techniques to adequately represent the dynamic response …
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PARALLEL INDEPENDENT COMPONENT ANALYSIS WITH REFERENCE FOR IMAGING GENETICS: A SEMI-BLIND MULTIVARIATE APPROACH
… tests used in univariate models. In contrast, a reference-guided multivariate approach shows specific advantage for simultaneously assessing many variables for aggregate effects while leveraging prior information. It can improve the robustness of the results compared to a fully blind approach. In …
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The photochemical and mechanochemical ring opening of cyclobutene from first principles
… opening of cyclobutene. We use the ab initio multiple spawning (AIMS) method in order to examine the short time dynamics of cyclobutene. We have integrated the COLUMBUS software package into AIMS, which contains analytical gradients and nonadiabatic couplings for multi-reference configuration …
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DEVELOPMENT OF HIGH LEVEL AB INITIO METHODS TO DESCRIBE NONADIABATIC EVENTS AND APPLICATIONS TO THE EXCITED STATES OF SMALL BIOLOGICAL MOLECULES
… to the point where high level methods, such as Multi-Reference Configuration Interaction (MRCI), are applicable to large molecular systems. Thus, to effectively study these systems, compromises must be made. In this work, two different approaches are taken to study the photophysical properties …
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Rapid Condition Assessment of Bridges By Falling Weight Deflectometer
<p>The objective of this thesis is to investigate the feasibility of using a Falling Weight Deflectometer (FWD) as an impact source to rapidly assess the condition of an in service bridge through the evaluation of its modal properties. Tests were conducted on two bridges, a Parker Pony Truss and a …
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Multi-Configurational Investigation of Thermolytic Pathways of Highly Strained Ring Systems
… for each structure were computed using the multi-configurational self consistent field method (MCSCF) with a cc-pVDZ basis set, while energies were computed using multi-reference Möller-Plesset second order perturbation theory (MRMP2) with a cc-pVTZ basis set. A multiconfigurational …
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Under the influence: Understanding the thermodynamic and optical properties of stimuli-responsive complex organic systems
… absorption peaks. In each case, a combination of multiple high-level state-of-the-art quantum-chemical approaches including DFT/MRCI (density functional theory/multi-reference configuration interaction) is utilised to thoroughly investigate the chemical systems and find explanations for the often …