Studies of anisotropic and isotropic Raman line shape yield information about the rotational motion (rotational correlation function) and non-reorientational (vibrational) lifetimes. The rotational motion of carbon disulfide has been studied previously by the techniques of Raman spectroscopy (6, 43), Rayleigh scattering (43, 46) and direct measurement (47). This work was...
A nonflame method for atomic absorption spectroscopy is
described. A helical tungsten filament from a commercially available
6-V, 4-A light bulb, heated to :incandescence in an argon atmosphere
is used to atomize 2-μl aqueous samples for metals analyses. Studies
of two hollow cathode lamp tungsten filament orientations, a
modulated light...
Ab initio calculations using the B3LYP and CCSD(T) methods were employed in this work to explore the most stable structure of the intriguing compound Be(BH₄)₂, for which as many as seven different structures have been proposed in the literature. Use of the B3LYP density functional method with several large basis...
Synthesis and discovery lies at the core of every field in chemistry. The investigation of the structure-property relationships in compounds known or new is the fundamental purpose of solid state chemistry. Mixing related solid state compounds to form solid solutions can lead to exciting new and/or unexpected properties. Layered compounds...
Transition metal oxides exhibit potential in various application fields due to the special d-electrons. Solid state chemistry focuses on discovering the structure-property relationships. The work in this thesis mainly discusses compounds with hexagonal or brownmillerite-type structure and their practical properties.
Hexagonal YIn[subscript 1-x]Fe[subscript x]O₃ (x = 0-0.3, 0.7-1.0) phases have...
The temporal and spatial characteristics of a laser microprobe plume were investigated using the spectroscopic methods of emission, absorption and fluorescence. The plume was produced by rapid vaporization of a small quantity (1 μg) of a solid sample using a focussed pulsed dye laser (110 MW/cm²). For absorption and fluorescence...
Plasma sources with multiple electrodes have been developed and
characterized in this research for atomic emission spectroscopy.
Multi-electrode plasma sources use electrodes to shape the plasma in
order to continuously entrain a sample stream in the center of hot
plasma, in a manner similar to an inductively coupled plasma (ICP)...
Applications of several methods of coherent nonlinear Raman Spectroscopy have been made in this thesis research. The theory and potential of one of these, Photoacoustic Raman Spectroscopy (PARS), is discussed in chapter two. Experimental results are presented which illustrate the sensitivity of this method and establish sampling conditions for maximum...
The techniques of coherent anti-Stokes Raman spectroscopy (CARS)
and inverse Raman spectroscopy (IRS) are used to examine carbon dioxide
aggregation in a supersonic jet expansion. To promote the formation of
small clusters, a BMW injector valve is modified to permit its use as a
pulsed nozzle at very cold temperatures....
While properties are extremely important from an application point of view, it is crucial to have a detailed understanding of the underlying structural influence. Once a concrete correlation between the structure and the observed property is established, rational design of novel materials with optimized properties can be realized. These optimized...
The carbon is photoelectron spectrum of CO₂ has been measured with very high photon energy resolution. The natural lifetime of the carbon is hole state has been determined from a series of spectra taken at photon energies of 308, 320, and 330 eV. The measured values of the lifetimes show...
The high resolution stimulated Raman spectrometer at OSU was
modified to improve its sensitivity and to extend its range of
applications to low Raman shifts and to the spectroscopy of solids and
liquids. As part of the characterization of the spectrometer, optical
Stark effects on rotational and vibrational transitions of...
High resolution spectroscopy was used to study the properties of two simple polyatomic molecules, sulfur trioxide, SO₃, and carbon suboxide, C₃O₂. The fundamental modes and several hot bands of the ¹⁸O isotopic fonns of SO₃ (³²S¹⁸O₃ and ³⁴S¹⁸O₃) have been investigated using both infrared spectroscopy and coherent anti-Stokes Raman scattering...
A new experimental apparatus was built at Oregon State University to perform high resolution stimulated Raman spectroscopy in a pulsed molecular jet at state densities of the order of 10¹¹ cm⁻³. The technique uses a stimulated Raman step to first populate a vibrational/rotational level and then a resonantly enhanced multiphoton...
The use of gas jets in a sputtering cell makes this direct sampling method practical for atomic absorption and mass spectrometry determinations. With a commercial six-jet sputtering source, the Atomsource (Analyte Corp., Grants Pass, Oregon), that directly atomizes solid samples for conventional atomic absorption spectrophotometers, the sample loss rate for...
Investigations of plasma production by a pulsed dye laser
microprobe were made. Comparisons between a Q- switched and a
pulsed dye laser system were made on the intensity of the continuum
produced by atmospheric breakdown. The dye laser system was
foundtominimize the production of the continuum which in turn
allowed...
The CARS apparatus at OSU was modified to permit studies in the 0-500 cm⁻¹ spectral region. The new low frequency capabilities were then used to study molecular clusters formed in free expansion jets of carbon dioxide. A strong cluster band was observed at 73 cm⁻¹, with a weaker shoulder at...
The development and applications of a 0.2 cm⁻¹ resolution
Nd-YAG laser powered coherent anti-Stokes Raman
spectroscopy, CARS, spectrometer for gas phase studies is
chronicled in this thesis. Applications including CARS
lineshape analysis, resonant CARS, and CARS of transient
species and excited state molecules is reported.
The intensity of the signal...
The temporal and spatial characteristics of the plume produced
by a laser microprobe, are dependent upon the composition and pressure
of the atmosphere surrounding it. It has been shown that certain atmospheres
can enhance the analytical signal by increasing the free
atom lifetime.
Improvements were made to the existing laser...
Understanding structural evolution in solids as composition changes is essential to materials properties prediction. Such structure-properties relationships are the theme of solid state chemistry. Materials scientists and chemists have utilized an abundance of simple crystal structures to enhance understanding of chemical and structural origins of properties in materials for decades....