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The structures, vibrational frequencies, and potential energy functions of several molecules in their ground and excited electronic states were determined using various spectroscopic and theoretical methods. High-level ab initio and density functional theory (DFT) calculations were utilized to investigate the previously reported structures and vibrational spectra of 1,3- disilacyclobutane (13DSCB) and its 1,1,3,3-d4 (13DSCB-d4) isotopomer. These calculations confirmed the finding from earlier microwave work that the CSiC angles of the 13DSCB ring are unexpectedly larger than the SiCSi angles. The calculated vibrational spectra using density functional theory agreed well with the experimental data and showed CH2 modes to have unusually low values. The calculations also confirmed that the individual molecules in the vapor phase are puckered whereas in the solid they become planar. The one-dimensional potential energy surfaces (PESs) for the ring inversion vibration of 2-cyclohexen-1-one and its 2,6,6-d3 isotopomer in its ground and singlet S1(n,π*) electronic states were determined using ultraviolet cavity ringdown spectroscopy (CRDS). The CRDS data allowed several of the quantum states of the ring inversion vibration to be determined for both the ground and excited electronic states, and the data were fit very well with PESs with high barriers to inversion. The infrared and Raman spectra and DFT calculations were utilized to complete a vibrational assignment of 2CHO and 2CHO-d3. A remarkable agreement was seen between the experimental and calculated spectra. The fluorescence excitation spectra (FES) and the single-vibronic level fluorescence (SVLF) spectra of jet-cooled 1,4-dihydronaphthalene (14DHN) were acquired to determine its ring-puckering potential energy function for the ground and singlet S1(π,π*) electronic states. Ultraviolet, infrared, and Raman spectra were also recorded to complement the analysis. The potential energy functions showed that the molecule is planar in both the ground and S1(π,π*) states. A complete vibrational assignment was carried out for 14DHN using the infrared and Raman data and aided by DFT calculations. The ab intio calculations carried out on 2-methyl-2-cyclopenten-1-one (2MCP) showed that the molecule can have 3 different conformers. Infrared and Raman spectra of the liquid-phase molecule were recorded and analyzed to complement the theoretical calculations.

The development of a co-axially configured submillimeter spectrometer is reported. The spectrometer has been constructed to observe molecular complexes that exhibit non-covalent interactions with energies much less than that of a traditional covalent bond. The structure of molecular complexes such as those formed between a rare gas and a hydrogen halide, Rg:HX where Rg is a rare gas (Rg=Ne, Ar and Kr) and HX (X=F, Cl, Br and I) can be determined directly and accurately. The center of mass interaction distance, RCM, as well as the angle of the hydrogen halide is determined, along with direct evaluation of the intermolecular vibrations as well as accurate isomerization energies between the hydrogen bound and van der Waals forms. The accuracy of the frequency determination of rovibrational transitions using the submillimeter spectrometer is also evaluated by direct comparison with the state-of-theart pulsed nozzle Fourier transform microwave spectrometer, and this accuracy is estimated to be less than 1 kHz at 300 GHz. The tunneling or geared bending vibration of a dimer of hydrogen bromide or hydrogen iodide has been investigated. The selection rules, nuclear statistics and intensity alternation for transitions observed in these dimmers, which is a consequence of interchanging two identical nuclei in the low frequency geared bending vibration of the molecular complex, are reported. Furthermore, the rotation and quadrupole coupling constants are used to determine a vibrationally averaged structure of the complex. The energy of the low frequency bending vibration can then be compared with ab initio based potential energy surfaces. A study of the multiple isomeric forms of the molecular complex OC:HI is also presented. Multiple isotopic substitutions are used to determine the relevant ground state structures and data reported evidence for an anomalous isotope effect supporting a ground state isotopic isomerization effect. All spectroscopic data that has been reported here has been additionally used to subsequently model and generate vibrationally complete morphed potential energy surfaces that are capable or reproducing the experimentally observed data. The utility of this procedure is evaluated on a predicative basis and comparisons made with newly observed data.

A new glucose affinity sensor based on a homogeneous fluorescence resonance energy transfer (FRET) assay system was developed to monitor the competitive binding between concanavalin A (ConA) and dextran. The FRET quenching kinetics of the donor were analyzed from frequency-domain (FD) measurements as functions of both glucose and acceptor-protein concentrations using a Förster-type decay kinetics model. The results showed that the FD measurements and donor decay kinetics can indicate quantitative changes in the presence of glucose at concentrations ranging from 0 to 224 mg/dL. The second set of experiments proved the feasibility of performing analyte sensing with FD lifetime spectroscopy using microsphere-based sensors in multiple scattering solutions. A well characterized pH-sensitive fluorophore was entrapped in poly(ethylene glycol) microspheres. The particles were then immersed in a buffered polystyrene solution of various pH. Measurements of phase shift and modulation of the generated and multiply scattered fluorescent light were acquired as the modulation frequency of the incident excitation light varied from 10 to 120 MHz. After the measured data were analyzed with the coupled diffusion equations, the obtained lifetimes from the scattering measurements matched values from non-scattering measurements. Lastly, a new two-speed Monte Carlo (MC) simulation was developed to predict light propagation through the sensors and thus was used to evaluate these sensors and to design these sensors for implantation. The model used random packing structure and considered geometric optics and two light propagation speeds. Experimental measurements of phase-shift and modulation of excitation light were made on a cubic phantom with non-fluorescent resin microspheres of 74 µm diameter, and compared to those computed from the MC simulation. The results showed that the mean phase shift (PS) deviation was 0.736° and the mean amplitude deviation was 42%. Quantitative changes in detected fluorescence phase-shift and modulation were investigated for microsphere diameter, volume fraction, refractive index, and fluorophore lifetime. We also found that even though the sensitivity of PS change in the presence of scattering was the same as the value without scattering, the values of PS were magnified due to the scattering effects.

Tunable diode laser spectroscopy and the Beer-Lambert relation has been used to measure the absorption of water vapor both in an absorption cell and in a shock tube. The purpose of this thesis is to develop a laser diagnostic capable of determining species concentration. The correlation between species concentration and absorption is known, and if one is known the other can be calculated. A diode laser was obtained which has a tunable range of 1325.7 - 1400.8 nm and is centered at 1384 nm. An experimental setup was created in which the laser was used to obtain absorption spectroscopy data for water vapor within two separate scenarios- in an absorption cell and in a shock tube. A model was constructed which enabled the calculation of the Voigt profile which in turn was used to determine the absorption coefficient and ultimately enable the utilization of absorption spectroscopy principles to determine species concentration and/or absorption percentage. The experiments for the absorption cell were performed at room temperature. Twenty runs were performed and the average error for all runs was less than one percent. Three runs were performed for the shock-tube experiments. The absorption was calculated at three times- prior to the arrival of the shock, after the incident shock passed, and after the reflected shock passed. The temperatures for these conditions were 296K, 1060K, and 2000K respectively. These experiments showed reasonable agreement with theoretical calculations.

Iron is an essential element for life. It is involved in a number of biological processes, including iron sulfur (Fe/S) cluster assembly and heme biosynthesis. However it is also potentially toxic due to its ability to induce formation of reactive oxygen species (ROS) via Fenton chemistry. Therefore its uptake, trafficking and utilization must be regulated to avoid its toxicological effect. It has been recently discovered that Fe/S cluster biosynthesis machinery plays a key role in the cellular iron regulation and its disruption leads to impaired iron regulation and iron accumulation within mitochondria. The iron accumulation resulted from impaired Fe/S cluster assembly in the eukaryotic model organism Saccharomyces cerevisiae (baker’s yeast) was studied. Various biophysical (e.g. Mössbauer, EPR, UV-vis spectroscopy) and biochemical (e.g. Western blots, PCR, enzyme activity assay, etc.) techniques were used to characterize the iron content in yeast mitochondria isolated from several mutants strains. In these mutants one of the proteins involved in Fe/S cluster biosynthesis (Yah1p and Atm1p) is mutated and iron regulation and metabolism are disrupted. By integrating the results obtained from these different methods, it was determined that excess iron accumulates in the mutant mitochondria as inorganic phosphate Fe(III) nano-particles exhibiting superparamagnetic behaviors. Oxygen is required for iron accumulation and nanoparticle formation. The Fe(III) nano-particles can be chemically reduced to Fe(II) then largely exported from the mitochondria. These biophysical and biochemical methods were also used to examine the iron distribution in whole yeast cells of the Aft1-1up strain in which iron regulon genes are constitutively activated and compared to that of Yah1p-depleted and wild type yeast. Constitutive activation of iron regulon genes does not alter the cellular iron distribution significantly. However disruption of Fe/S cluster assembly by Yah1p depletion causes dramatic cellular iron redistribution: the vacuolar iron is largely evacuated and most of the cellular iron probably precipitates in mitochondria as Fe(III) nanoparticles. The results provide novel insights into iron trafficking and possible signal communications between organelles within cells.

Diamond-Like carbon (DLC)films have received a considerable amount ofwear resistant overcoat and biocompatible coatings. attention recently due to their chemical stability, high optical transparency and hardness. These properties make the films suitable for a number of applications such as protective and anti-reflection coating. Due to environmental pollution, double or multilayered coatings were recently developed as a new generation of protective coating. The present development hybrid coating system HBS900,is combination of hard coatings titanium nitride (TiN) and titanium carbonitride (TiCN) as multilayer are generated by cathode arc vaporization and magnetron sputtering, then on it following is high quality of diamond-like carbon film deposited by high degree of ionization, high densities of ions of electron cyclotron resonance plasma in the same recipient. It made the tools longer lifetime combination of outer lubrication layer. Not only using the high resistance and wear out of the inter multilayer, but also increasing the adhesion of DLC. The structural characteristics of DLC films were investigated by Raman spectroscopy, standard scratch, pin-on-disk test and microhardness. It made the film more graphite-like by higher substrate bias, higher process pressure, and higher ECR power The characteristics of the back stamper surface coated by DLC film were improved, and the productivity of an optical disk per stamper was estimated at about 1.7 times more than obtained. The properties of DLC films coating on the tamper were obtained and summarized as follows: excellent adhesion 65N, and coefficients of friction less than 0.15. As a result of adapting a microdrill coated with DLC film, the drilling lifetime was significantly improved to reach about 2.5 times than that of the uncoated one. The purpose of this research was to deposit the protective diamond-like carbon (DLC) films on polycarbonate substrates for optical applications. The oxygen plasma pretreatment of the substrate surface, silicon-incorporated diamond-like carbon films (DLC-Si), and the coating deposition conditions can enhance the adhesion of the DLC film. The coated DLC film showed better adhesion on the PC substrate surface under three tests as the alcohol rub test, a tape pull test, and a thermal shock test. The reactive CH4 (30sccm), the substrate bias (-100 V), the RF power (300 W), and In experiments, it is preceded being focus on the analysis of Raman spectrum for the films grown at various CH4 gas fluxes, substrates bias voltages, and higher si-doping concentrations made the film the better characteristics, the lower surface roughness, and higher hardness and adhesion. At least, the properties of diamond-like carbon (DLC) film coatings on phase-change recording media were characterized by Raman spectroscopy, atomic force microscope (AFM), UV-visible spectrometer and disc testers. The dependence of mechanical, optical and structural properties of DLC films included the characteristics of surface roughness, hardness, transmittance and electrical signals of discs on serveral DLC film thicknesses were investigated. Our experimental results indicate that DLC films provide a suitable coating to protect PC substrate and make it no difference for data stored on phase-change optical discs.

We discove the decrement,comparing the Electroreflectance spectroscopy of theforward biased voltage is 0.5V after the photon energy is 1.8eV.We discuss the case from Asymptotic form and the sample.

The electroreflectance (ER) of surface-intrinsic-n+ type doped GaAs has exhibited many Franz-Keldysh oscillations to enable the application of fast Fourier transform to separate the heavy and light-hole transitions. In this work, we can get the dependence of surface electric field on external biased voltage from analyzing the Franz- Keldysh oscillations and the way of fast Fourier transform on condition that weakly modulated field, further more we can get the dependence of effective reduced mass on changed photon energy.