B. M. Kincaid

Bio: B. M. Kincaid is an academic researcher from Bell Labs. The author has contributed to research in topics: Undulator & Extended X-ray absorption fine structure. The author has an hindex of 9, co-authored 14 publications receiving 1976 citations.

Extended x-ray absorption fine structure—its strengths and limitations as a structural tool

Abstract: The authors review the development of extended x-ray absorption fine structure (EXAFS) within the last decade. Advances in experimental techniques have been largely stimulated by the availability of synchrotron radiation. The theory of EXAFS has also matured to the point where quantitative comparison with experiments can be made. The authors review in some detail the analysis of EXAFS data, starting from the treatment of raw data to the extraction of distances and amplitude information, and they also discuss selected examples of applications of EXAFS chosen to illustrate both the strength and limitations of EXAFS as a structural tool.

Transferability of Phase Shifts in Extended X-Ray Absorption Fine Structure

Abstract: Phase shifts in extended x-ray-absorption fine-structure (EXAFS) measurements have been empirically determined for atom pairs. For photoelectron energies g 100 eV it is shown that these phase shifts, because they are essentially independent of chemical environment, can be used with EXAFS spectra to determine interatomic distances typically to accuracies of 0.02 \AA{}.

Random errors in undulators and their effects on the radiation spectrum

Abstract: Undulators and wigglers are central components of free-electron lasers and proposed new high-brightness synchrotron radiation light sources. This paper explores the effects of random field errors on the performance of practical undulators. An approximate theory of these effects is derived, along with limiting conditions on its validity. The result of this work is a description of the loss of radiated intensity by two universal functions. The functions’ arguments are simple combinations of the basic undulator parameters. Simple numerical simulation methods are presented, and numerical results are compared with the predictions of the universal functions. Finally, possible solutions to the problem of random errors in undulators are discussed.

Carbon K Edge in Graphite Measured Using Electron-Energy-Loss Spectroscopy

Abstract: We have measured the carbon $K$ edge in graphite using inelastic-electron-scattering spectroscopy. The extended x-ray absorption fine structure is in good agreement with theory for the first-neighbor atoms at a distance of 1.42 \AA{}. The momentum dependence of the edge structure is in qualitative agreement with a simple band-structure picture. A comparison of the signal counting rates for electron-energy-loss and photoabsorption experiments shows that the energy-loss method is competitive with synchrotron radiation sources up to about 1000 eV.

The structural and luminescence properties of porous silicon

Abstract: A large amount of work world-wide has been directed towards obtaining an understanding of the fundamental characteristics of porous Si. Much progress has been made following the demonstration in 1990 that highly porous material could emit very efficient visible photoluminescence at room temperature. Since that time, all features of the structural, optical and electronic properties of the material have been subjected to in-depth scrutiny. It is the purpose of the present review to survey the work which has been carried out and to detail the level of understanding which has been attained. The key importance of crystalline Si nanostructures in determining the behaviour of porous Si is highlighted. The fabrication of solid-state electroluminescent devices is a prominent goal of many studies and the impressive progress in this area is described.

First-principles calculations for point defects in solids

Abstract: Point defects and impurities strongly affect the physical properties of materials and have a decisive impact on their performance in applications. First-principles calculations have emerged as a powerful approach that complements experiments and can serve as a predictive tool in the identification and characterization of defects. The theoretical modeling of point defects in crystalline materials by means of electronic-structure calculations, with an emphasis on approaches based on density functional theory (DFT), is reviewed. A general thermodynamic formalism is laid down to investigate the physical properties of point defects independent of the materials class (semiconductors, insulators, and metals), indicating how the relevant thermodynamic quantities, such as formation energy, entropy, and excess volume, can be obtained from electronic structure calculations. Practical aspects such as the supercell approach and efficient strategies to extrapolate to the isolated-defect or dilute limit are discussed. Recent advances in tractable approximations to the exchange-correlation functional ($\mathrm{DFT}+U$, hybrid functionals) and approaches beyond DFT are highlighted. These advances have largely removed the long-standing uncertainty of defect formation energies in semiconductors and insulators due to the failure of standard DFT to reproduce band gaps. Two case studies illustrate how such calculations provide new insight into the physics and role of point defects in real materials.

Extended x-ray absorption fine structure—its strengths and limitations as a structural tool

Abstract: The authors review the development of extended x-ray absorption fine structure (EXAFS) within the last decade. Advances in experimental techniques have been largely stimulated by the availability of synchrotron radiation. The theory of EXAFS has also matured to the point where quantitative comparison with experiments can be made. The authors review in some detail the analysis of EXAFS data, starting from the treatment of raw data to the extraction of distances and amplitude information, and they also discuss selected examples of applications of EXAFS chosen to illustrate both the strength and limitations of EXAFS as a structural tool.

Reactivity of Surface Species in Heterogeneous Catalysts Probed by In Situ X-ray Absorption Techniques

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