Nonlinear optical processes can be described as multiphoton scattering events in terms of high order perturbation theory. The standard procedure for quantitative calculation of high order terms is to impose a steady state condition on the perturbative radiation fields. In the present work, this condition will be lifted, and explicit...
Perturbed Angular Correlations (PAC) spectroscopy is an effective
local probe technique often employed in the characterization of defects or
phase transitions in any of a variety of materials. This technique relies
upon the ability of probe nuclei to function as gauges of the magnetic
fields and electric field gradients local...
The effect of ultra-high pressure on the thermal emf of a
chromelialumel thermocouple is investigated using an indirect
method which does not require a direct knowledge of the temperature
of the pressurized junction. The unknown temperature is written
parametrically as a function of a directly measured quantity, the
electrical power...
In order to understand better the defect structure and dynamics associated
with lower valent dopants complexed with native defects in group IV oxides, In/Cd
perturbed angular correlation spectroscopy was performed in ceria and zirconia. Examining
the orientation symmetry axis of defects in ceria single crystals at low temperature
has allowed...
Electric fields due to adsorbates on a metal surface are studied experimentally with Rydberg atoms as probes. A beam of lithium Rydberg atoms, produced by an oven in a high-vacuum system, passes within 3μm of the surface of a metal mesh having 6μm square openings. Rydberg states with principal quantum...
Semi-insulating, powder samples of Cadmium Telluride (CdTe) have been studied using ¹¹¹In Time Differential Perturbed Angular Correlation (PAC) Spectroscopy. The samples have been lightly doped (~10¹² cm⁻³) with ¹¹¹In atoms, which occupy well-defined metal (Cd) lattice sites and act as probes of the local environment. These substitutional donors form a...
Research was conducted to determine the thermoelectric behavior of Co₉S₈, Co₉Se₈, CoSe, CoTe₂, CoSbSexSl-x (x=O, 0.25, 0.50, 0.75, 1.0), CoSbTe, AuTe₂, AuTe₁.₉₀Sb₀.₁₀, Au₀.₉₅Pt₀.₀₅Te₂, Au₀.₉₅Ag₀.₀₅Te₂, MnTe₂, MnTe₁.₉₅Sb₀.₀₅, MnTe₁.₉₀Sb₀.₁₀, CoSb₂, and Co₀.₉₅Fe₀.₀₅Sb₂. Recently discovered sodium cobalt oxide compounds have been found to have large Seebeck coefficients coupled with favorable thermal and electrical...
The behavior of all of the observed molecular band
emission as well as the prominent atomic line emission
from a pulsed microwave helium plasma is given. Extensive
efforts to purify the helium include the use of a
uranium getter, a quartz diffusion tube, and a cataphoretic
discharge. The plasma is...
In order to observe laser phase noise, this noise must be converted to
amplitude noise, which can be achieved using either an interferometer or an
absorption resonance in an atomic/molecular vapor or gas. When phase noise is
converted to amplitude noise, it is manifested as a heterodyne signal in the...
Measurements are made of the conductivity and Hall mobility of
liquid solutions of thallium-tellurium, in compositions ranging from
pure tellurium to 69.0 atomic percent thallium. At compositions on
the thallium-rich side of intrinsic composition (66.7 atomic percent
thallium) both the conductivity and Hall mobility are temperature
independent, and the data...
The purpose of this project is to verify scattering mechanisms in semiconductors by measuring transport properties and producing data that reflects existing research. The Hall effect is utilized to measure the resistivity, mobility and charge carrier concentration of the semiconductors: indium tin oxide (ITO), p-type silicon, and n-type silicon. By...
In this work the electron energy distribution functions and the
anisotropic drift term of the velocity distribution functions in non-self-sustaining
(Townsend) discharges in argon were determined by
direct measurement for a range of E/N (electric field strength by
gas atom concentration) from 70 to 407 Townsends (Td). (One Td
equals...
This investigation represents a previously unreported method
of measurement of internal friction in single crystals of silicon. The
method consists of exciting a rectangular reed of silicon of uniform
cross section into forced vibration at its resonant frequency. The end
of the reed is silver plated and eddy currents induced...
Temporal variations in individual spectrum lines
emitted by a microwave discharge in pure helium are
investigated: The discharge is produced in a quartz tube
located inside of a section of waveguide which carries
pulsed 3 centimeter microwaves. The helium used is purified by a three-fold process consisting of treatment with...
A high-temperature, high-pressure autoclave has been
adapted for use with a high-field nuclear magnetic
resonance spectrometer. The autoclave has an internal
pressure range of atmospheric pressure to 1.5 kbar and a
temperature range of 273 K to 1900 K. The autoclave is
usable in a high field (8 T) magnet...
The drift velocity of electrons in pure hydrogen, in pure deuterium, and in mixtures thereof, has been observed at low pressures using the following pulse technique for these gases for the first time. Plane parallel electrodes of a known separation and immersed in the gas to be studied are connected...
Amorphous multicomponent metals have promising applications in novel electronic devices because of their atomically smooth surface morphology and lack of grain boundaries. It is important to understand the thermal transport properties of amorphous metals and an accurate measurement of their thermal conductivity will be essential for further improvement of device...
Hall measurements can be made on the unstudied alloy, Sn₁-ₓCaₓSe to determine its electrical transport properties. The Sn₁-ₓCaₓSe samples were made by laser deposition into thin films and have a variable of calcium concentration x. These samples are approximately 250 nm in thickness, were grown at 366° C and are...
A great concern about the effect of oxygen in Se samples has been solved by a purification method called the distillation-with-Al method. The electrical conductivity of liquid Se prepared by this purification method shows Arrehnius behavior with a single activation energy and positive thermopower within the experimental temperature range. This...
The fact that measuring a quantum system reduces it to apparently classical behavior, eliminating the interference patterns that are a hallmark of quantumness, cries out for an explanation. That explanation has been provided by the recognition of decoherence,whereby the interference is destroyed by the very interaction that acquires information.We begin...