Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"excited electronic states"”.
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Experimental and Theoretical Study of Resonance Raman Spectroscopy in Ground and Excited Electronic States
… to understand the effects of intramolecular electronic and nuclear structure on the Raman intensities of molecules with extended π conjugation. Conjugated thiophene derivatives have a variety of interesting optical and electronic properties, which makes them ideal targets for studies of …
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Collisional transfer between excited electronic states as a mechanism for sulfur mass-independent fractionation
… cm⁻¹) in S₂ as a proxy for study of excited state collisional transfer as a possible mechanism for S-MIF. The short-lifetime B state (natural lifetime: 32 ns) state-mixes extensively with a longer-lifetime B" state (4200 ns).
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Beschreibung angeregter Molekülzustände in komplex strukturierter Umgebung durch einen effizienten, individuell selektierenden MRCI-Algorithmus gekoppelt an ein molekularmechanisches Kraftfeld
… computational demand due to the involvement of excited electronic states, we (i) largely speed up the individually selecting multi-refernce configuration interaction (IS/MRCI) scheme by Tavan and Schulten (1980) by a new grahical algorithm and (ii) take use of recently developed semimempirical …
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Excited State Chemical Dynamics: Beyond the Born-Oppenheimer Approximation
… of molecular systems in nonequilibrium, and excited electronic states using the tools of non-adiabatic molecular dynamics will be built up from the full molecular Hamiltonian and associated quantum mechanical equation of motion. This common formalism, from which all of the approximate methods …
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ΦΑΣΜΑΤΟΣΚΟΠΙΑ ΔΙΕΓΕΡΜΕΝΩΝ ΗΛΕΚΤΡΟΝΙΑΚΩΝ ΚΑΤΑΣΤΑΣΕΩΝ ΤΩΝ ΠΙΚΟΛΙΝΩΝ
… HAS TO DO WITH THE SPECTROSCOPY OF THE EXCITED ELECTRONIC STATES OF PICOLINES (METHYLPYRIDINES). SPECIFICALLY THE ABSORPTION SPECTRA WERE RECORDED IN THE GAS PHASE IN THE REGION OF 4-9.5 JEV. FROM THESE WEMEASURED THE EXTINCTION COEFFICIENT AND THE OSCILLATOR STRENGTH FOR THE DIFFERENT …
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Theoretical investigation of the quantum-confined Stark effect
… <p>The understanding of the basic physics of excited electronic states is an important consideration when developing new methods and applications. In this dissertation, excited electronic states were studied using the electron-hole quasiparticle representation. Theoretical treatment of …
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Spectroscopy of Ultracold LiRb Molecules Using Ionization Detection
… a free-bound transition to create weakly bound excited state molecules in a process known as photoassociation (PA). We explore weakly bound vibrational levels of LiRb with PA spectroscopy using ionization detection and, where possible, compare our results with earlier measurements performed in …
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Tddft Derivative Couplings And Other Topics In Quantum Chemistry
… reactions, which involve both the ground and excited electronic states of a molecule, can promote processes otherwise inaccessible by normal reactions. In general, photochemical reactions may be classified as adiabatic or nonadiabatic depending on whether the reaction takes place on the same …
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Direct QM/MM Simulations of the Excited State Dynamics of Retinal Protonated Schiff Base in Isolation and in Complex Environments
… method is used to describe the ground and excited electronic states of the chromophore and the environment is represented with an empirical force field (QM/MM). The potential energy surfaces and their couplings are determined "on the fly," i.e. simultaneously with the dynamic evolution. We …
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Development of multicomponent coupled-cluster theory and its application to nanoclusters and molecular systems
… is not valid. The first is when nuclear and electronic motion cannot be decoupled. Decoupling the motion leads to incorrect observations and conclusions drawn. The second case is when a chemical system has more than one type of particle to be treated without the Born-Oppenheimer …
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Theoretical Studies on the ultrafast photodissociation of molecules
… an intersection between the ground and first excited state. As a consequence the dissociation occurs on both states. We use two models to study this system, a 2D and a 6D, contrasting greatly in their complexity and ability to describe the whole molecule. Wavepacket dynamics are used to probe …
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Photochemical and computational study of sulfoxides, sulfenic esters, and sulfinyl radicals
… was study computationally and the ground and excited electronic states using ab-initio and density functional methods. The coupling reaction of sulfinyl radicals is also investigated. The reaction of the methylthiyl radical with oxygen was also investigated us the G2 method.</p>
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Single-conformation spectroscopy of hydrogen bonding networks: Solvation, synthetic foldamers, and neurodegenerative diseases
… their effect on DPOE’s pair of closely spaced excited electronic states. These experimental studies provide excellent insight into solvent effects on vibronic and excitonic coupling, and can be used to further develop the models used to describe such processes.</p> <p>Similarly, …
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Experimental Studies of LiRb: Spectroscopy and Ultracold Molecule Formation by Photoassociation
… the production of ultracold LiRb molecules in excited electronic states by photoassociation (PA). We report the measurements of the <em>C<sub>6</sub></em> coefficients for the Li (2<em>s</em> <sup>2</sup>S<sub>1/2</sub>) + Rb (5<em>p</em> <sup>2</sup>P<sub>1/2</sub>) and the Li (2<em>s</em> …
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Solid-State NMR of Metallic and Paramagnetic Systems
… can also provide important details of the electronic and magnetic structure for a sample. In this work ssNMR methodologies are developed to study different paramagnetic and metallic systems, and thereby demonstrate the information that can be obtained. These strategies include investigating …
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Thermal cis-trans isomerization of azobenzene studied by path sampling and QM/MM stochastic dynamics
… Fast switching can be induced via transitions to excited electronic states and fine-tuned by a large number of different substituents at the phenyl rings. But a rational design of tailor-made azo groups also requires control of their stability in the dark, the half-lifetime of the cis isomer. In …
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Extension and applications of the GVVPT2 method to the study of transition metals
<p>The ground and low-lying excited electronic states of molecules of the first ( 2 Sc , 2 Cr , 2 Mn , and 2 Ni ) and second ( 2 Y , 2 Mo , and 2 Tc ) row of transition elements have been investigated for the first time with the generalized Van Vleck second order multireference perturbation theory …
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Laser-control of molecular dynamics
… modes, and the population transfer between electronic states. Although it was not tried to optimize the fields to gain higher yields, the control was found to be very efficient. Driving population transfer in a double well potential could be shown to take place with nearly 100% efficiency. …
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Coupled electron and nuclear dynamics in model systems
… been discussed in the stationary case, nor for excited electronic states or for a coupled electronic and nuclear motion. In order to remove these restrictions one must describe the quantum mechanical motion of all particles in a system at the same level. This is only possible for very small …
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Estados eletrônicos e rotovibracionais da molécula de água no Sol
Um refinamento na análise do espectro de absorção IV das manchas solares permitiu a identificação de 67 novas bandas, que agora se somam as 185 já identificadas como transições rotovibracionais da molécula de água. Os resultados revelam transições dentro do mesmo nível vibracional assim como …