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Showing 1 to 20 of 63 for “"Vibronic"”.
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Decoherence and Dephasing of Vibronic Excitons /
… of the exciton dynamics, therefore the vibronic exciton theory has to be used. In this thesis, the significance of dephasing and decoherence of vibronic excitons in molecular systems is investigated and the signatures of electronic-vibrational interaction in the two-dimensional …
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Excited states of chromophores and vibronic interactions
… focus of my Ph.D. work has been on building a vibronic coupling model for multichromophores and extending that model to more general systems. This Dissertation serves as both a summary of this work as well as a manual for the two vibronic coupling programs I have written. It is my hope that the …
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To Couple or not to Couple? Exploring Vibronic Coupling in Organic Semiconductors
… with nuclear motion. In particular, vibronic coupling governs many key performance metrics, including emission linewidth, radiative efficiency, charge separation rates, and non-radiative losses. The interaction between electronic excitations and vibrational degrees of freedom not only …
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A study of the molecular behavior in the vibronic and excitonic properties of silicon nanoparticles
The molecular behavior of silicon nanoparticles, produced via electrochemical etching of a bulk precursor, is studied. The smallest particle, 1 nrn in diameter, is amenable to first principles modeling due to the manageable number of atoms in the structure. The ability to produce these particles in …
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Vibroninių eksitonų išsifazavimas ir dekoherencija /
… of the exciton dynamics, therefore the vibronic exciton theory has to be used. In this thesis, the significance of dephasing and decoherence of vibronic excitons in molecular systems is investigated and the signatures of electronic-vibrational interaction in the two-dimensional …
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Investigations of intramolecular dynamics by picosecond time-resolved spectroscopy
… relaxation processes of the initially prepared vibronic level. Fluorescence depletion decays and dispersed fluorescence spectra of 19 vibronic features in the isolated gas phase molecule p-cyclohexylaniline are presented. The excellent match of the laser system's tuning curve with the …
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Picosecond Time-Resolved Fluorescence Depletion Spectroscopy of Fluorene: IVR in the Excited Electronic State
… decays and dispersed fluorescence spectra of 19 vibronic features of fluorene are presented. The decays show a progression of dynamic behavior including stationary behavior at low densities of states, quantum beating at intermediate densities, and fast decay of the initially prepared state at …
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Two-photon absorption and nonlinear polariton effects in organic crystals
… a nitrogen laser-pumped dye laser. Analysis of vibronic structure reveals that the dominant intermediate states for TPA are those of B(,2) (L axis) symmetry. TPE spectra principally associated with intermediate states of A(,1) (M) symmetry exhibit strong intramolecular vibronic coupling by …
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Vibrational Spectroscopy and Potential Energy Surface Analysis of the X˜ And B˜ States of Thiophosgene
Nearly 1,000 B˜(1A 1) → X˜(1A 1) vibronic transitions of SCCl2, originating from eight B˜(1A1) state vibrational levels, have been measured by dispersed fluorescence spectroscopy. More than 370 of these vibrational fundamentals, overtones, and combination bands were assigned …
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Two-dimensional Spectroscopy of Molecular Excitons in a Model Dimer System
… provide clear signatures for coherences between vibronic excitons in 2D spectra. We begin by describing the design of a broadband passively phase-stabilized interferometer for collection of 2D spectra, which also allows for the investigation of state preparation in 2D spectroscopy by using shaped …
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Laser-Induced Fluorescence Studies of Molecular Dynamics
The vibronic rovibronic fluoresence excitation spectra of biacetyl, methylglyoxal, and pentanedione have been recorded for the excited singlet state of each molecule. In particular, the fluorescence of biacetyl in a molecular beam has been shown to exhibit the quantum beat effect in the …
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Theoretical Studies on the ultrafast photodissociation of molecules
… between the nuclear and electron motion: termed vibronic coupling. A known feature in potential energy surfaces due to vibronic coupling is the conical intersection and these play a role in all three systems studied. In the first study we investigate NH\(_3\), which exhibits an intersection …
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Investigation of chiral porphyrin aggregates with heterodyne-detected vibrational sum frequency generation spectroscopy
… HD-VSFG experiments can also probe excitonic and vibronic characteristics via experimental double resonance. By use of polarization conditions, theoretical modeling, and computational fitting, detailed information on the orientation of vibrational, vibronic, and excitonic transition dipoles can be …
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On The Nature Of Excited States In Ruthenium Complexes: Towards Renewable Energy
… coupled to electronic transitions (evident from vibronic side band features in emission spectra). Density functional theory (DFT) has indicated that the excited state distortions for these systems are due to electronic mixing of Ru-bpy 3MLCT excited state with the bpy ligand and * orbitals, or …
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Supersonic jet spectroscopy of synthetic foldamers, multichromophores, and their water containing clusters
… the intrinsic properties of the close lying, vibronically coupled excited states. Whether incorporated in the same molecule or present as separate monomers, the excited state properties depend on the distance, relative orientation, and strength of the electronic coupling between the two …
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An analysis of the photoelectron and Rydberg states of formaldehyde /|nby Carol R. Lessard. -- 260 St. Catharines [Ont.] : Dept. of Chemistry, Brock University,
… perturb each other through pseudo-Jahn-Teller vibronic coupling. The vacuum ultraviolet spectrum contains a number of features which are difficult to explain, and two unusually sharp bands can only be identified as representing some form of electron promotion in formaldehyde.
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Proton-coupled electron transfer in molecular and material catalysis
… reaction, and the results show that the vibronic coupling is dependent on the molecular geometry. This diagnostic is important for the calculation of PCET rate constants. The rate constants and kinetic isotope effects for concerted PCET in a set of hydroquinone derivatives are calculated …
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The Electronic and Vibrational Spectroscopy of Matrix-Isolated Phthalocyanines – Experiment and Theory
… of isolation. The spectral positions of the vibronic bands in emission with pulse dye laser excitation for both Pcs have been identified. A comparison of the fluorescence spectra with Raman spectra in KBr pellets has revealed very strong similarities. This is entirely consistent with the …
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Spectroscopic characterization and photochemistry of nitrogen-containing molecules relevant to Titan's atmosphere
… understanding Titan's atmospheric chemistry. The vibronic spectroscopy of <em>para</em>-diisocyanobenzene (<em>p</em>DIB, C≡N-Ph-N≡C) has been characterized as a first step towards photochemical studies that can test the transformation of the isonitrile group to other nitrogen-based …
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Dynamically motivated spectroscopy of small polyatomic molecules
… of the C̃ state of SO₂, which arises due to vibronic interactions that lead to non-equivalent equilibrium SO bond lengths.
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