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Vibrational and thermal behavior of several important systems were studied. The first study was a measurement of the infrared vibrational spectra of glucose and two important glucose dimers (cellobiose and maltose) as a function of temperature. The purpose of his study was to measure shifts in vibrational band positions to gain insight into carbohydrate reactivity. The second study was on hydrothermally treated coffee waste biomass. Here, collaborators at University of Campinas (UNICAMP, Brazil) treated coffee waste biomass in a flow-through subcritical water hydrolysis reactor. The purpose of the M.S. study on coffee waste was to understand the chemical changes that occurred to the residual solids during hydrolysis treatment. Vibrational spectroscopy and thermal analysis techniques were used. The third and final study was to understand the chemical composition of the solid product resulting from co-solvent enhanced lignin fractionation (CELF) of several biomass feeds. Collaborators at University of California Riverside (UCR) recently developed the CELF process. The purpose of the M.S. study on the CELF solid product was to understand its composition to help guide the CELF reactor design and determine applications for the CELF solids. Taken together, the 3 studies are integrated into a cohesive whole that demonstrates the use of spectroscopic and thermal techniques for characterizing biomass and understanding its composition at the molecular level.

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The matching of colours on dyed fabric is an important task in the textile industry. The current method is based on the matching the visible reflectance spectrum to standard spectral libraries. In this study, the amount of dye on various wool and wool-blend fabric was measured using vibrational-spectroscopic techniques. FT-IR PAS and FT-Raman spectroscopy was used to analyse the following set of samples: woollen fabrics (supplied by CSIRO- Geelong, Australia), dyed with Lanasol dyes (Red 6G, Blue 3G and Yellow 4G) and wool/polyester fabrics (supplied by Ceiba-Geigy, Switzerland), dyed with Forosyn dyes (grey, yellow, green, brown, orange, red). A minimum of six spectra was recorded for each sample. The spectra recorded were consistent with those reported previously. FT-IR PA spectral data were block normalised with Y-mean centring and examined using Principle Component Analysis (PCA) and Partial Least Squares (PLS). Although PCA separates the woollen fabrics dyed with a combination of two colours, it does not do equally well for samples dyed with three colours. The dyed wool/ polyester blend samples appeared in a totally random fashion on the PCA plot. The PLS analysis of PA spectra of various ratios of dyes on woollen fabrics as well as wool/polyester blend was found to be a viable procedure and should be investigated further, perhaps with a broader set of data. FT-Raman spectra were examined using PCA and PLS. The best pre treatment for FT-Raman spectral data was found to be normalising followed by Y-mean centring. The PCA plots demonstrate that woollen samples are separated according to the dye ratios and that the presence or absence of some of the peaks is influenced by individual dyes. For example, the presence of the peak at 1430cm 1 is inversely related to the presence of blue dye on the fabric. The PLS resulted in SEE and SEP values of around 1 and 2 respectively indicating that the prediction of the dye ratios have not been very successful and suggesting that there was some problem with the measured values of the calibration set. PCA plots of wool/polyester fabrics dyed with a single colour indicate that PC1 separates the samples according to how close the shades are together, while PC2 and PC3 separate samples according to their individual colours. PC4, although explaining only a small percentage of variance, suggests that the samples are not homogeneously dyed. PCA plots of the samples dyed with various combinations of the three main dyes display each cluster of samples in their right position on the colour card. Calculated SEE and SEP values (Yellow: ~0.30, ~0.55, Brown: ~0.30, ~0.79, Red: 0.16, 0.49 and Grey: ~0.2, ~0.40, respectively) indicate that FT-Raman spectroscopy and chemometrics may offer promising methods for measuring the ratio of various dyes on wool/polyester fabrics. FT-Raman spectroscopy and chemometrics were also used to investigate the change in the ratio of dyes on UV-treated dyed woollen samples. Samples were weathered for 7 and 21 days, using accelerated weathering instrument. The substrate subtracted spectral data were normalised to 100% substrate of the first derivative (9 points and 7 degrees) followed by double centring of the matrix in the spectral region of 1500-500cm-1. PCA effectively separated non-irradiated from the irradiated sample but did not separate the irradiated samples further according to the number of days of irradiation. The pre-treatment used for PLS was first derivative of substrate subtracted spectral data normalised to 100% substrate, and then Y-mean centred. PLS failed to predict the ratio of the irradiated dyes very well. This may be because degradation products are not modelled by PLS or because the total amount of dye has reduced without changing the dye ratios.

The electronic and vibrational spectra of Ni+(H2O) were measured using photofragment spectroscopy. In the electronic spectrum, photodissociation is observed at photon energies above 16875 cm-1. The only fragment observed is Ni+. The electronic spectrum consists of well-resolved peaks spaced by ~340 cm-1, due to a vibrational progression in the excited electronic state. These peaks have complex sub-structure, consisting of a triplet, spaced by ~30 cm-1. The sub-structure is due to rotational structure in a perpendicular transition of a prolate top molecule. In addition to this major progression, there is a series of less intense, single peaks spaced by ~340 cm-1. These may be due to a vibrational progression in a second electronic state, this time due to a parallel transition. The O-H stretching vibrations of Ni+(H2O) were measured using vibrationally mediated photodissociation (VMP) in a depletion experiment, only monitoring transitions from K’’=1. This revealed a O-H symmetric stretch at 3629 cm-1 and antisymmetric O-H stretch at 3692 cm-1. Several electronic structure calculations complement the experiments using the BHandHLYP hybrid density functional and the 6-311++G(3dp, f) basis set. At this level of theory, Ni+(H2O) is predicted to have C2v symmetry and 2A1 ground state. The Ni-O bond length is 1.95, the O-H bond lengths are .955 and the H-O-H angle is 108.2˚ The molecule is a near-prolate top, with rotational constants A=13.98 cm-1, B=0.297 cm-1 and C=0.296 cm-1 . Analysis of the electronic and vibrational spectra reveals that binding to Ni+ removes electron density from the oxygen lone pairs, increasing the H-O-H bond angle from its value in bare H2O. The electronic and vibrational spectra corresponds to 4s ¬3d transistion in Ni+. As a result of electronic excitation, the Ni-O bond stretches by .20 Å, and the H-O-H bond angle is reduced.

No / Spectroscopic techniques have the potential to provide powerful, molecular-specific, non-invasive measurements on polymers during melt processing operations. An exploration is reported of the application and assessment of sensitivity of in-process vibrational spectroscopy¿on-line mid-infrared (MIR), on-line near-infrared (NIR), in-line NIR and in-line Raman¿for monitoring of single screw extrusion of high-density polyethylene and polypropylene blends. These vibrational spectroscopic techniques are compared with novel in-line ultrasound velocity measurements, which were acquired simultaneously, to assess the sensitivity of each method to changes in blend composition and to explore the suitability for their use in real time process monitoring and control.

Current study of separation mechanism in chromatography heavily relies on the measurement of macroscopic properties, such as retention time and peak width. This dissertation describes the vibrational spectroscopy characterization of separation processes.Raman Spectroscopic characterization of a silica-based, strong anion exchange stationary phase in concentrated aqueous solutions is presented. Spectral response of stationary phase quaternary amine is closely related to changes in interaction between counter anions and the amine functional groups as the result of anion hydration. The molecular-level information obtained will provide useful guidance for control of stationary phase selectivity.To study the effects of stationary phase pore size on separations processes, monodisperse silica particles in the sub-100 nm range are prepared and self-assembled to well-ordered, three-dimensional colloidal arrays. A modified LaMer model is proposed and demonstrated for optimization of reaction conditions that lead to uniform and spherical silica particles. This approach greatly reduces the number of training experiments required for optimization. Fast Fourier transformation of colloidal array scanning electron microscopy images indicates closely-packed hexagonal packing patterns.Using these arrays, a novel system for the measurement of molecular diffusion coefficients in nanopores is reported. This system consists of an ordered colloidal array with well-defined pore structure deposited onto an internal reflection element for in-sit collection of kinetic information by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). A mathematical model is established to extract diffusion coefficients from these data. A decrease of approximately eight orders of magnitude in molecular diffusion coefficients is observed for molecular transport in nanopores.Finally, by using this colloidal array-ATR-FTIR system and the corresponding mathematical models that describe absorption in the colloidal array, the distribution in the nanopores of the acetonitrile organic modifier in an aqueous mobile phase solvent system is determined. Based on the results of 50 nm colloidal arrays, pore surface properties have a strong effect on the distribution of organic molecules from bulk solution to the pores.

The molecular conformations, potential energy functions and vibrational spectra of several cyclic molecules have been investigated by ab initio and density functional theory calculations and by infrared and Raman spectroscopy. The ab initio computations of 3-cyclopenten-1-ol predict that its lowest energy conformer has a weak pi-type intramolecular hydrogen bonding. The three other conformers lie 301 to 411 cm^-1 higher in energy. The infrared and Raman spectra of this molecule confirm the presence of the four conformers. The energy difference between the two conformers of lowest energy was also determined from the experimental spectroscopic data and was found to be 435 plus/minus 160 cm^-1, in reasonable agreement with the ab initio computations results. Ab initio calculations for cyclopentane and d1, 1,1-d2, 1,1,2,2,3,3-d6, and d10 isotopomers confirm cyclopentane confirmed that has twist and bent structures and that these differ in energy by less than 10 cm^-1. The bending angle is 41.5 degrees and the twisting angle is 43.2 degrees. A complete vibrational assignment for each of the isotopomers was achieved. Ab initio calculations were also carried out for methylcyclopropane, cyclopropylsilane, cylopropylgermane, cyclopropylamine, cyclopropanethiol and cyclopropanol. The structure and the potential energy function for internal rotation was calculated for each and compared to available experimental results determined from infrared and Raman spectra. The calculated barriers to internal rotation agree very well with the experimental data. The structures, relative energies, and frequencies for the lowest energy vibrations of the twisted, bent, and planar forms of cyclohexene and four of its oxygen analogs were calculated and compared to experimental results. The calculated structural data agree very well with that from the microwave work, but the computed barriers are somewhat lower than those based on far-infrared data. 4-Silaspiro-(3,3)-heptane possesses two four-membered rings, each puckered with and angle of 34 degrees. The molecule possesses a two-dimensional ring-puckering potential energy surface with four equivalent minima. The ab initio calculations predict a barrier to planarity of each ring of 582 cm^-1 while the energy of the structure with both rings planar is 1220 cm^-1 higher. The calculated infrared and Raman spectra were compared to those previously published, and the agreement is excellent.