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Search Publications by: Bruce D. Ravel (Fed)

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Displaying 26 - 50 of 99

A Synchrotron X-ray Micro-Spectroscopy Study of the Explosive Melt Glass Derived From the Trinity Nuclear Test

April 28, 2019
Author(s)
Bruce D. Ravel, Daniel E. Crean, Daniel J. Bailey, M. C. Stennett, Claire L. Corkhill, Ryan Tappero, N. C. Hyatt
Trinitite, the explosive melt glass derived from the Trinity nuclear test, is of interest as a model material for nuclear forensics investigation. However, there remains uncertainty as to the mechanism of trinitite formation. In this study, new insight is

Non-Resonant Valence-to-Core X-ray Emission Spectroscopy of Niobium

March 23, 2018
Author(s)
Bruce D. Ravel, A. J. Kropf, Dali Yang, Mengen Wang, Mehmet Topsokal, Deyu Lu, M. C. Stennett, N. C. Hyatt
The valence-to-core (V2C) portion of X-ray Emission Spectroscopy (XES) measures the electron 15 states close to the Fermi level. These states are involved in bonding, thus provide a measure of the 16 chemistry of the material. In this manuscript, we show

The effect of self-consistent potentials on EXAFS analysis

November 1, 2017
Author(s)
Bruce D. Ravel, M. Newville, Josh J. Kas, John J. Rehr
We present an EXAFS-oriented theory program based on the popular Feff8 and providing an application programming interface designed to make it easy to integrate high-quality theory into EXAFS analysis software. We then use this new code to examine the

Ultrafast time-resolved x-ray absorption spectroscopy of ferrioxalate photolysis with a laser plasma x-ray source and microcalorimeter array

February 17, 2017
Author(s)
Galen C. O'Neil, Joel N. Ullom, Luis Miaja Avila, Young Il Joe, Joseph W. Fowler, Carl D. Reintsema, Daniel S. Swetz, Kevin L. Silverman, Daniel R. Schmidt, Bruce D. Ravel, Gene C. Hilton, William B. Doriese, Bradley K. Alpert, Ralph Jimenez
Using a table-top apparatus based upon a laser plasma x-ray source and an array of cryogenic microcalorimeter x-ray detectors, we have measured the transient x-ray absorption spectrum during the ferrioxalate photoreduction reaction. We observe the Fe K

XAFS Data Interchange: A single spectrum XAFS data file format

June 9, 2016
Author(s)
Bruce D. Ravel, M. Newville
We propose a standard data format for the interchange of XAFS data. The XAFS Data Interchange (XDI) standard is meant to encapsulate a single spectrum of XAFS along with relevant metadata. XDI is a text-based format with a simple syntax which clearly

Abiotic bromination of soil organic matter

October 15, 2015
Author(s)
Bruce D. Ravel, Alessandra C. Leri
Biogeochemical transformations of plant-derived soil organic matter (SOM) involve complex abiotic and microbially mediated reactions. One such reaction is halogenation, which occurs naturally in the soil environment and has been associated with enzymatic

Muffin tin potentials in EXAFS analysis

September 1, 2015
Author(s)
Bruce D. Ravel
Muffin tin potentials are the standard tool for calculating the potential surface of a cluster of atoms for use in the analysis of extended x-ray-absorption fine-structure (EXAFS) data. The set of Cartesian coordinates used to define the positions of atoms

Understanding the blue color in antique mosaic mirrored glass from the Temple of the Emerald Buddha, Thailand

February 4, 2015
Author(s)
Bruce D. Ravel, Wantana Klysubun, Christoph Hauzenberger, Prapong Klysubun, Yuying Huang, Weeraya Wongtepa, Panidtha Sombunchoo
Two samples of the blue glass produced in the middle 19th century from the Temple of the Emerald Buddha in Bangkok, Thailand, were studied in order to understand the origin of its blue color. The oxide components and trace elements are quantitatively

Path degeneracy and EXAFS analysis of disordered materials

October 24, 2014
Author(s)
Bruce D. Ravel
The analysis of EXAFS data measured on a material with a disordered local configuration environment around the absorbing atom can be challenging due to the proliferation of photoelectron scattering paths that must be considered in the analysis. In the case