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Articles 1771 - 1800 of 1821

Full-Text Articles in Physics

A Comparison Of The Rough Sphere Rotational Diffusion Model With Experimental Results For Liquid Methyl Iodide, Dane R. Jones, Scott L. Whittenburg, C. H. Wang Sep 1976

A Comparison Of The Rough Sphere Rotational Diffusion Model With Experimental Results For Liquid Methyl Iodide, Dane R. Jones, Scott L. Whittenburg, C. H. Wang

Chemistry and Biochemistry Faculty Publications

No abstract available.


18th Annual Rocky Mountain Spectroscopy Conference Aug 1976

18th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Final program and abstracts from the 18th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 2-3, 1976.


17th Annual Rocky Mountain Spectroscopy Conference Aug 1975

17th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Final program and abstracts from the 17th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 4-8, 1975.


16th Annual Rocky Mountain Spectroscopy Conference Aug 1974

16th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Final program and abstracts from the 16th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 5-6, 1974.


15th Annual Rocky Mountain Spectroscopy Conference Aug 1973

15th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 15th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 20-21, 1973.


Radiative And Predissociative Lifetimes Of The A ²Σ+ State Of Oh, Richard Orlin Sutherland, Richard A. Anderson Feb 1973

Radiative And Predissociative Lifetimes Of The A ²Σ+ State Of Oh, Richard Orlin Sutherland, Richard A. Anderson

Chemistry Faculty Research & Creative Works

Lifetime measurements have been made on the A 2Σ+ state of OH by the delayed coincidence technique in conjunction with an interrupted rf discharge through water vapor. Lifetimes are reported for rotational states up to K=29 and K=20 in the ν=0 and ν=1 vibrational levels, respectively, and on the unresolved levels of ν=2. A predissociation, previously predicted from relative intensity measurements, resulting from a curve crossing by the repulsive 4Σ− state, was observed for the rotational states above K=23 of ν=0, for those above K=14 of ν=1, and for all those of ν=2. These lifetime data are discussed qualitatively in …


14th Annual Rocky Mountain Spectroscopy Conference Jul 1972

14th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 14th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, July 31 - August 1, 1972.


Mössbauer-Effect Studies Of The Phase Transitions In Antiferroelectric Pbzro₃ And Ferroelectric Pbti₀.₀₂Zr₀.₈O₃, James P. Canner, C. M. Yagnik, Robert Gerson, William Joseph James Nov 1971

Mössbauer-Effect Studies Of The Phase Transitions In Antiferroelectric Pbzro₃ And Ferroelectric Pbti₀.₀₂Zr₀.₈O₃, James P. Canner, C. M. Yagnik, Robert Gerson, William Joseph James

Physics Faculty Research & Creative Works

The Mössbauer spectra were studied for the antiferroelectric compound PbZrO3 and for the closely related ferroelectric PbTi0.2Zr0.8O3. In both cases, a substitution of 5-mol% BiFeO3 was made to permit the Mössbauer measurements. Little difference was found in the isomer shift in these compounds, whether they were in the ferroelectric, antiferroelectric, or cubic state, indicating that the bonding character is not affected by the transitions among the states. There was a pronounced and approximately equivalent dip in the recoil-free fraction at the Curie points of both the antiferroelectric and ferroelectric materials, associated with …


Evidence For The Existence Of Two Stable Sites For Cobalt Impurity Atoms In Aluminum, Arun Venkatachar Aug 1971

Evidence For The Existence Of Two Stable Sites For Cobalt Impurity Atoms In Aluminum, Arun Venkatachar

Dissertations and Theses

Using Fe57Mössbauer spectroscopy, two alternative sites occupied by cobalt (10-4 at. % ) impurity atoms in aluminum have been isolated. The substitutional site A is the stable position after annealing the sample above 840 K, followed by a rapid quench. The impurity atoms in site A are characterized by a single line Mössbauer spectrum (indicative of a cubic environment), a room-temperature f = 0.502 (r. m. s. displ. 0.071 A) and an I. S. (reI. to Fe) = -0.421 mm/sec. For anneals below 770 K the cobalt atoms migrate to site B, which is characterized by a …


13th Annual Rocky Mountain Spectroscopy Conference Aug 1971

13th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 13th annual meeting of the Rocky Mountain Spectroscopy Conference, hosted by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 9-10, 1971.


Ion‐Pair Theory Of Concentrated Electrolytes. Iii. Variational Principle, Frank Stillinger, Ronald White Apr 1971

Ion‐Pair Theory Of Concentrated Electrolytes. Iii. Variational Principle, Frank Stillinger, Ronald White

Center for Advanced Mineral and Metallurgical Processing (CAMP)

Two major contributions are devised for that theory of concentrated electrolytes which by convention regards the ions as completely paired into uncharged dipolar “molecules.” First, a more satisfactory expression is obtained for the wavelength‐dependent static dielectric “constant” ε(k). Second, a variational principle for Helmholtz free energy F is displayed whose minimization with respect to the ion‐pair size distribution p(1) serves to determine both F and p(1). In anticipation of future numerical applications, a binary collision approximation is specified for the short‐range interaction aspect of the functional F[p(1)].


Ion‐Pair Theory Of Concentrated Electrolytes. Iv. Ion Atmosphere Charge Distribution, Frank Stillinger, Ronald White Apr 1971

Ion‐Pair Theory Of Concentrated Electrolytes. Iv. Ion Atmosphere Charge Distribution, Frank Stillinger, Ronald White

Center for Advanced Mineral and Metallurgical Processing (CAMP)

Arguments are presented indicating that the large‐size limiting behavior of the ion‐pair size distribution is qualitatively the same both with, and without, Coulomb interactions between ions. This in turn implies that the static dielectric response function ε0 / ε(k) derived in the preceding paper is nonanalytic at k = 0. The specific singular behavior of this response requires a branch cut along the imaginary k axis. It furthermore induces an r−8 tail in the ion atmosphere charge distribution at finite electrolyte concentration.


Mössbauer Studies Of Bifeo₃-Pbtio₃ Perovskite-Type Solid Solutions, C. M. Yagnik, Robert Gerson, William Joseph James Jan 1971

Mössbauer Studies Of Bifeo₃-Pbtio₃ Perovskite-Type Solid Solutions, C. M. Yagnik, Robert Gerson, William Joseph James

Physics Faculty Research & Creative Works

The Mössbauer spectra of the ferroelectric solid solutions (BiFeO3)x(PbTiO)1-x have been studied as a function of temperature, mainly between room temperature and 600°C, using 57Fe in the solutions as an absorber. The quadrupole splitting increased and the isomer shift decreased between x = 0.05 and x = 0.70, a range in which the solutions are tetragonal and paramagnetic, and in which the unit cell volume increases with increasing x. The isomer shift, in particular, was primarily determined by the unit cell volume. Data are presented on the internal magnetic field of the antiferromagnetic …


Perturbation Theory Of The Hooke's Law Model For The Two‐Electron Atom, Ronald White, W. Byers Brown Nov 1970

Perturbation Theory Of The Hooke's Law Model For The Two‐Electron Atom, Ronald White, W. Byers Brown

Center for Advanced Mineral and Metallurgical Processing (CAMP)

The Hooke model for the two‐electron atom replaces the electron–nuclear interaction by a harmonic oscillator potential, but retains the Coulomb repulsion of the electrons. The first‐order perturbation equation for the electron repulsion is solved analytically, and the exact first‐, second‐, and third‐order perturbation energies are obtained. A similar Z-1 perturbation treatment is carried out for the Hartree–Fock equation and other variational approximations. The Z-1 of the correlation energy is compared with that for helium-like atoms and found to be similar.


Investigation Of The Alpha-Sub-Gamma Phase In Alnico 6, Cortez Samuel Sep 1970

Investigation Of The Alpha-Sub-Gamma Phase In Alnico 6, Cortez Samuel

Dissertations and Theses

The purpose of this research project was to study the αᵧ phase in Alnico 6. Other phases were studies for comparison. Also the effect of an applied magnetic field on the formation of the αᵧ phase was investigated.

Three single crystals of Alnico 6 were heat treated for one hour--one at 1250°C, one at 1000°C, and one at 800°C--and water-quenched. The microstructure of each sample was observed with the optical microscope, and X-ray diffraction patterns were taken to determine the crystal structure of the phases present.

Several single crystal samples of Alnico 6 were heat treated at 1000°C and furnace-cooled. …


12th Annual Rocky Mountain Spectroscopy Conference Aug 1970

12th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 12th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 3-4, 1970.


Analytic Approach To Electron Correlation In Atoms, Ronald White, Frank Stillinger Jun 1970

Analytic Approach To Electron Correlation In Atoms, Ronald White, Frank Stillinger

Center for Advanced Mineral and Metallurgical Processing (CAMP)

A novel perturbative treatment of electron correlation in N‐electron atoms is devised. The unperturbed starting point is a central‐force “hydrogenic” problem in the full dN‐dimensional configuration space (d = dimensionality). The central potential in this solvable “hydrogenic” problem is obtained by averaging the actual electron–electron and electron–nucleus potentials over all dN − 1dN − 1 hyperspherical polar angles in the configuration space. The relevant projected Green's functions are computed for the ground states of the model one‐dimensional two‐electron atom (with delta function interactions), as well as for the real three‐dimensional helium isoelectronic sequence. The corresponding first‐order wavefunctions exhibit weakly singular …


Theory Of Droplet Growth In Clouds. I. The Transient Stage Of The Boundary-Coupled Simultaneous Heat And Mass Transport In Cloud Formation, John C. Carstens, Joseph T. Zung Jan 1970

Theory Of Droplet Growth In Clouds. I. The Transient Stage Of The Boundary-Coupled Simultaneous Heat And Mass Transport In Cloud Formation, John C. Carstens, Joseph T. Zung

Physics Faculty Research & Creative Works

Two solutions to the system of equations describing the simultaneous heat and mass transport involved in the condensational growth of a droplet in a supersaturated atmosphere are presented. The first, valid for very short times, describes the transient stage of such growth; the second, valid for longer times, presupposes the establishment of a steady-state condition. The two are shown to be complementary for the cases examined. The equations examined satisfy the usual boundary conditions imposed on a drop in a concentric sphere as required by the cellular model for cloud formation. Hence our results can be immediately extended to the …


On The Physical Properties Associated With Omega Phase In Titanium-Chromium Alloys, Serag El Din El Sayed Habib Jan 1970

On The Physical Properties Associated With Omega Phase In Titanium-Chromium Alloys, Serag El Din El Sayed Habib

Archived Theses and Dissertations

No abstract provided.


Mössbauer Effect In The Ferroelectric Pbtio₃-Bifeo₃ Solid Solutions, C. M. Yagnik, James P. Canner, Robert Gerson, William Joseph James Nov 1969

Mössbauer Effect In The Ferroelectric Pbtio₃-Bifeo₃ Solid Solutions, C. M. Yagnik, James P. Canner, Robert Gerson, William Joseph James

Physics Faculty Research & Creative Works

The Mössbauer spectra of the system (PbTiO3)0.95(BiFeO3)0.05 have been studied from room temperature to 585°C. From the isomer-shift of 0.491±0.02 mmsec-1 at room temperature, the ionicity is found to be 60% ± 20%. A discontinuity in the plot of isomer-shift versus temperature at Tc is observed. The quadrupole splitting at room temperature is 0.295 ± 0.02 mm/sec-1. A dip in the Mössbauer fraction is observed at the Curie temperature.


11th Annual Rocky Mountain Spectroscopy Conference Aug 1969

11th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 11th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 4-5, 1969.


Semiempirical Determination Of The Hydrogen Bond Energy For Water Clusters In The Vapor Phase. I. General Theory And Application To The Dimer, Richard W. Bolandee, James L. Kassner, Joseph T. Zung Jan 1969

Semiempirical Determination Of The Hydrogen Bond Energy For Water Clusters In The Vapor Phase. I. General Theory And Application To The Dimer, Richard W. Bolandee, James L. Kassner, Joseph T. Zung

Physics Faculty Research & Creative Works

A simple semiempirical method is given for determining the hydrogen bond energy for water clusters in the vapor phase. This method is based on a general statistical-mechanical theory of clustering. The partition function for a system of clusters is used to determine the equilibrium distribution of clusters. In conjunction with available thermodynamic and spectroscopic data, the cluster equilibrium constants can be used to calculate the cluster potential energy and the hydrogen bond energy. Results for the water dimer agree quite well with other reported values obtained either by quantum-mechanical calculations or approximate thermodynamic estimates. A correct temperature dependence of the …


10th Annual Rocky Mountain Spectroscopy Conference Aug 1968

10th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 10th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 19-20, 1968.


Perturbation‐Theoretic Approach To Potential‐Energy Curves Of Diatomic Molecules, Robert Parr, Ronald White Aug 1968

Perturbation‐Theoretic Approach To Potential‐Energy Curves Of Diatomic Molecules, Robert Parr, Ronald White

Center for Advanced Mineral and Metallurgical Processing (CAMP)

A perturbation theory is developed whereby the diatomic molecular potential energy W(R) as a function of the internuclear distance R is expressed, for R near Re, as a power series in the parameter λ = 1 − (Re/R), W(λ) = w0 + (wn − wn-1n.

Truncations of this series have the form of finite power series in R−1. The quantities wn are obtained simply as perturbation energies for a purely kinetic‐energy perturbation at Re, by setting up the problem in confocal elliptic coordinates, in …


Dielectric Properties Of Solid Solutions Of Bifeo₃ With Pb(Ti, Zr)O₃ At High Temperature And High Frequency, Robert Travis Smith, Gary D. Achenbach, Robert Gerson, William Joseph James Jan 1968

Dielectric Properties Of Solid Solutions Of Bifeo₃ With Pb(Ti, Zr)O₃ At High Temperature And High Frequency, Robert Travis Smith, Gary D. Achenbach, Robert Gerson, William Joseph James

Physics Faculty Research & Creative Works

Solid solutions of BiFeO3 with PbTiO3, PbTi0.5Zr0.5O3, and PbZrO3 were prepared. The crystallographic data on these solutions, which are basically perovskitic, are given. The dielectric constants of the materials were determined at a frequency of 0.53 GHz and at temperatures up to 800°C. Dielectric Curie points were found in solutions containing up to 90 mole % BiFeO3. These results leave little doubt that BiFeO3 is ferroelectric or antiferroelectric. The extrapolated Curie point for BiFeO3 is above 850°C. BiFeO3 appears more likely to be ferroelectric than …


Properties And Structure Of Some Chalcogenide Glasses, Amin Ismail Amin Abdel-Latif Jan 1968

Properties And Structure Of Some Chalcogenide Glasses, Amin Ismail Amin Abdel-Latif

Archived Theses and Dissertations

No abstract provided.


Catalytic Decomposition Of Hydrogen Peroxide By Manganese-Doped Magnesium Hydroxide, Nabih Philobbos Kelada Jan 1968

Catalytic Decomposition Of Hydrogen Peroxide By Manganese-Doped Magnesium Hydroxide, Nabih Philobbos Kelada

Archived Theses and Dissertations

No abstract provided.


9th Annual Meeting Rocky Mountain Spectroscopy Conference Aug 1967

9th Annual Meeting Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Program and abstracts from the 9th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 7-8, 1967.


Integral Series Solution Of The Schrödinger Equation For The Helium Atom, W. Byers Brown, Ronald White Jun 1967

Integral Series Solution Of The Schrödinger Equation For The Helium Atom, W. Byers Brown, Ronald White

Center for Advanced Mineral and Metallurgical Processing (CAMP)

No abstract provided.


Analytic Power-Series Solution Of The Schrödinger Equation For The Helium Atom, W. Byers Brown, Ronald White Jun 1967

Analytic Power-Series Solution Of The Schrödinger Equation For The Helium Atom, W. Byers Brown, Ronald White

Center for Advanced Mineral and Metallurgical Processing (CAMP)

No abstract provided.