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Full-Text Articles in Chemistry

Calculation Guided Rational Design And Synthesis Of Novel Cationic Fluorescent Meso–Pyridinium Bodipys For Bio-Imaging, Daniel J. Lamaster Oct 2018

Calculation Guided Rational Design And Synthesis Of Novel Cationic Fluorescent Meso–Pyridinium Bodipys For Bio-Imaging, Daniel J. Lamaster

LSU Doctoral Dissertations

Chapter 1 contains a brief overview of the history, synthesis, and properties of BODIPY dyes as well as that of the biomedical applications of bio-imaging and photodynamic therapy. Additionally, an overview of the theoretical framework of density functional theory and its time-dependent variant are provided. In Chapter 2, the effects of structural modification on the electronic structure and electron dynamics of cationic meso-(4-pyridyl)-BODIPYs were investigated. A library of 2,6-difunctionalized meso-(4-pyridyl)-BODIPYs bearing various electron-withdrawing substituents was designed and DFT calculations were used to model the redox properties, while TDDFT was used to determine the effects of functionalization on the excited …


Ultrafast And Nonlinear Spectroscopy Of Nanomaterials, Rami Anthony Khoury Jul 2018

Ultrafast And Nonlinear Spectroscopy Of Nanomaterials, Rami Anthony Khoury

LSU Doctoral Dissertations

Ultrafast and nonlinear spectroscopies are implemented in the investigation of excited-state dynamics and structural properties of materials and nanomaterials. In the first study, the excited-state dynamics of size-dependent colloidal TiO2-Au nanocomposites are investigated using ultrafast transient absorption spectroscopy. The dynamics corresponding to the plasmon depletion band are characterized by electron-phonon and phonon-phonon coupling lifetimes that are observed to be independent of the gold nanocluster shell thickness. The excited-state dynamics corresponding to the interband transition of gold is also spectrally overlapped with the interfacial electron transfer lifetime, which is shown to decrease as the nanocluster shell thickness increases. In …


Accelerated Broadband Spectra And Attosecond Charge Migration Simulations Using Real-Time Time-Dependent Density Functional Theory, Adam S. Bruner Jun 2018

Accelerated Broadband Spectra And Attosecond Charge Migration Simulations Using Real-Time Time-Dependent Density Functional Theory, Adam S. Bruner

LSU Doctoral Dissertations

In this dissertation, the calculations of light-matter interactions offer insight into the structure and dynamical response of electrons in molecular systems. Such information is useful for characterizing molecules, electronic structure, photochemistry, photomaterials, and a host of other applications. In the first part of this work, simulations of broadband absorption spectra are accelerated by the use of Pad´e approximanants of Fourier Transforms and dipole decomposition. Electronic absorption spectra from valence and core levels are obtained using time-dependent methods and compared to results from established perturbative techniques. In addition, core level absorption spectra are calculated for a nickel porphyrin and shown to …


Investigation Of Structure And Dynamics Of Deep Eutectic Solvent Using Infrared Spectroscopy, Yaowen Cui Jun 2018

Investigation Of Structure And Dynamics Of Deep Eutectic Solvent Using Infrared Spectroscopy, Yaowen Cui

LSU Doctoral Dissertations

Deep Eutectic Solvents (DES) are liquid mixtures prepared from solids. As a new class of green solvents, DES not only share many properties with ionic liquids, such as low volatility, conductivity, tailorable constituents, but also have some advantages over ionic liquids, like easier preparation, safe and inexpensive materials, biodegradability, low toxicity, and excellent solubility. Because of those attractive properties, DES has been studied in many scientific and engineering fields. However, compared with the great number of studies of the application, many questions about structure and dynamics of DES are unanswered. To shed light on the mystery of solvent or solvation …


Innovative Monte Carlo Methods For Sampling Molecular Conformations, Aliasghar Sepehri Feb 2018

Innovative Monte Carlo Methods For Sampling Molecular Conformations, Aliasghar Sepehri

LSU Doctoral Dissertations

Sampling molecular conformations is an important step in evaluating physical, mechanical, hydrodynamic, and optical properties of flexible molecules especially polymers. One powerful method for this purpose is configurational-bias Monte Carlo in which one random segment of a molecule is chosen, all segments toward one random end are removed, and then regrown segment by segment to produce a new geometry to be accepted/rejected according to probability laws. The advantage of this method is the ability to generate acceptable conformations that are favorable for intra- and intermolecular energies to save computational costs. However, when there are several interdependent energetic terms, trial generation …