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Full-Text Articles in Physics

Argon-Photoion–Auger-Electron Coincidence Measurements Following K-Shell Excitation By Synchrotron Radiation, Jon C. Levin, C. Biedermann, N. Keller, L. Liljeby, C.-S. O, R. T. Short, Ivan A. Sellin, Dennis W. Lindle Aug 1990

Argon-Photoion–Auger-Electron Coincidence Measurements Following K-Shell Excitation By Synchrotron Radiation, Jon C. Levin, C. Biedermann, N. Keller, L. Liljeby, C.-S. O, R. T. Short, Ivan A. Sellin, Dennis W. Lindle

Chemistry and Biochemistry Faculty Publications

Argon photoion spectra have been obtained for the first time in coincidence with K-LL and K-LM Auger electrons, as a function of photon energy. The simplified charge distributions which result exhibit a much more pronounced photon-energy dependence than do the more complicated noncoincident spectra. In the near-K-threshold region, Rydberg shakeoff of np levels, populated by resonant excitation of K electrons, occurs with significant probability, as do double-Auger processes and recapture of the K photoelectron through postcollision interaction.


Low-Temperature Epitaxial Growth Of Thin Metal Films, James W. Evans, D. E. Sanders, Patricia A. Thiel, Andrew E. Depristo Mar 1990

Low-Temperature Epitaxial Growth Of Thin Metal Films, James W. Evans, D. E. Sanders, Patricia A. Thiel, Andrew E. Depristo

Chemistry Publications

We present a different mechanism to explain the occurrence of long-lived oscillations in diffraction spot intensities during epitaxial growth of metal films on fcc (100) substrates at low temperature. Rather than rely on the common picture of cyclical nucleation and growth to produce the oscillations, the model invokes ‘‘downward funneling’’ deposition dynamics to fourfold-hollow adsorption sites.


Coincidence Orientations Of Crystals In Tetragonal Systems, With Applications To Yba2cu3o7, Abha Singh, N. Chandrasekhar, Alexander H. King Jan 1990

Coincidence Orientations Of Crystals In Tetragonal Systems, With Applications To Yba2cu3o7, Abha Singh, N. Chandrasekhar, Alexander H. King

Alexander H. King

We have developed a method for the characterization of coincidence-site lattices (CSL's) in tetragonal or near-tetragonal orthorhombic structures, by suitable modifications to the method of Grimmer & Warrington [Acta Cryst. (1987), A43, 232-243]. We have applied our method to determine coincidence rotations and the associated information appropriate for forming constrained CSL's in the high-To superconductor YBazCu307-n. The unit cell is orthorhombic with lattice parameters a = 3.82, b = 3"89 and c = 11.67 A for the nominal composition. We present tables of coincidence rotation angles, .Z, CSL, DSCL and associated step vectors up to ,~ = 50. We find our ...


Topics In Theoretical Surface Science: I Structures Of Clean And Adsorbate Covered Surfaces Ii Epitaxy Of Metals On Metal Surfaces , Todd Joseph Raeker Jan 1990

Topics In Theoretical Surface Science: I Structures Of Clean And Adsorbate Covered Surfaces Ii Epitaxy Of Metals On Metal Surfaces , Todd Joseph Raeker

Retrospective Theses and Dissertations

The energetics and structures of clean and adsorbate covered surfaces are investigated in this dissertation. First, the formalism, within the Corrected Effective Medium (CEM) method, for calculating the surface energy of a clean surface is derived. The surface energies for many different metals and their low index surfaces are presented. The minimization of the surface energy is then used to predict the multilayer relaxation of the Al(111), (100), (110), Ni(100), (110) and Fe(100) surfaces. The driving forces behind surface relaxation is then examined within the CEM method;Extensions of the surface CEM formalism to calculate the binding ...


Path Integral Study Of The Correlated Electronic States Of Na4–Na6, Randall W. Hall Jan 1990

Path Integral Study Of The Correlated Electronic States Of Na4–Na6, Randall W. Hall

Collected Faculty and Staff Scholarship

Feynman’s path integral formulation of quantum mechanics is used to study the correlated electronic states of Na4–Na6. Two types of simulations are performed: in the first, the nuclei are allowed to move at finite temperature in order to find the most stable geometries. In agreement with previous calculations, we find that planar structures are the most stable and that there is significant vibrational amplitude at finite temperatures, indicating that the Born–Oppenheimer surface is relatively flat. In the second type of simulation, the nuclei are held fixed at symmetric and asymmetric geometries and the correlated electron density is ...