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Full-Text Articles in Physical Sciences and Mathematics
Optical Spectroscopy And Chemometrics For Discrimination Of Dyed Textile Fibers And Magnetic Audio Tapes, Nathan C. Fuenffinger
Optical Spectroscopy And Chemometrics For Discrimination Of Dyed Textile Fibers And Magnetic Audio Tapes, Nathan C. Fuenffinger
Theses and Dissertations
This dissertation focuses on the application of both novel and standard chemometric approaches toward societal problems of interest in the areas of forensic science and cultural heritage preservation. Microspectrophotometry (MSP), a technique enabling measurements of absorption of electromagnetic radiation by microscopic materials in the ultraviolet-visible (UV-Vis) region, is widely used by forensic examiners for comparisons of metameric textile fibers. These comparisons are often hindered, however, by the raw or normalized spectra showing little detail or having few points of comparison. Derivative preprocessing can enhance structure in some instances. We have demonstrated through the use of multivariate statistics that derivatives are …
Differentiation Of Human, Animal And Synthetic Hair By Atr Ftir Spectroscopy, Jeremy Manheim
Differentiation Of Human, Animal And Synthetic Hair By Atr Ftir Spectroscopy, Jeremy Manheim
Chemistry
Hair fibers are ubiquitous to every environment and are the most commonly found form of trace evidence at crime scenes. The primary difficulty forensic examiners face after retrieving a hair sample is determining who it came from. Currently, the methodology of microscopic examination of potential hair evidence is absent of statistical probability and is inherently subjective. Another method, involving DNA analysis, takes months to conduct and the majority of times is unsuccessful due to its degradation and absence from the hair. Here, Attenuated Total Reflectance (ATR) Fourier Transform Infrared (FTIR) Spectroscopy coupled with advanced statistics was used to identify a …
The Spectroscopic Characterization Of Newly Developed Emissive Materials And The Effects Of Environment On Their Photophysical Properties, Louis Edward Mcnamara
The Spectroscopic Characterization Of Newly Developed Emissive Materials And The Effects Of Environment On Their Photophysical Properties, Louis Edward Mcnamara
Electronic Theses and Dissertations
The development of new materials capable of efficient charge transfer and energy storage has become increasingly important in many areas of modern chemical research. This is especially true for the development of emissive optoelectronic devices and in the field of solar to electric energy conversion. The characterization of the photophysical properties of new molecular systems for these applications has become critical in the design and development of these materials. Many molecular building blocks have been developed and understanding the properties of these molecules at a fundamental level is essential for their successful implementation and future engineering. This dissertation focuses on …
Photoelectrons And Recombining Electrons In Atomic And Molecular Systems, Kristen D'Ann Fulfer
Photoelectrons And Recombining Electrons In Atomic And Molecular Systems, Kristen D'Ann Fulfer
LSU Doctoral Dissertations
This work in this dissertation explores how photoelectrons enter and exit atoms and molecules. The electron rescattering events which may occur during photoionization or photorecombination processes play a dominant role in the understanding of how photoelectrons enter and exit molecules, which is intrinsically linked to how chemical reactions occur. Chapters 3-4 of this dissertation present evidence of vibrational mode specific breakdown of the Franck-Condon Principle in the photoionization of low symmetry molecules, acrolein and the singly halogenated thiophenes, due to resonant and non-resonant electron rescattering dynamics. In Chapters 5-6, the disentanglement of the valence electronic structure, as well as evidence …
Investigating The Photorecombination Dynamics In Molecular High-Harmonic Spectra, Benjamin Parker Wilson
Investigating The Photorecombination Dynamics In Molecular High-Harmonic Spectra, Benjamin Parker Wilson
LSU Doctoral Dissertations
The work presented in this dissertation will relate the photorecombination dynamics to photoionization dynamics in SF6 utilizing the self-probing mechanism, high harmonic generation (HHG). This work specifically aims to establish parameters for which the comparison is applicable and the macroscopic complications inherent in HHG do not interfere with the extraction of dynamic information. The first part of this work established the macroscopic experimental apparatus necessary for consistent spectroscopic observation. It is shown that using a gas jet that is an order of magnitude shorter than the Rayleigh length of the driving laser results in more consistent harmonic spatial profiles and …