High resolution x-ray fluorescence spectroscopy - a new technique for site- and spin-selectivity

Thesis/Dissertation · Sun Dec 01 04:00:00 EST 1996

DOI:https://doi.org/10.2172/456318· OSTI ID:456318

Wang, Xin ^[1]

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1. Univ. of California, Davis, CA (United States). Dept. of Applied Science

X-ray spectroscopy has long been used to elucidate electronic and structural information of molecules. One of the weaknesses of x-ray absorption is its sensitivity to all of the atoms of a particular element in a sample. Through out this thesis, a new technique for enhancing the site- and spin-selectivity of the x-ray absorption has been developed. By high resolution fluorescence detection, the chemical sensitivity of K emission spectra can be used to identify oxidation and spin states; it can also be used to facilitate site-selective X-ray Absorption Near Edge Structure (XANES) and site-selective Extended X-ray Absorption Fine Structure (EXAFS). The spin polarization in K fluorescence could be used to generate spin selective XANES or spin-polarized EXAFS, which provides a new measure of the spin density, or the nature of magnetic neighboring atoms. Finally, dramatic line-sharpening effects by the combination of absorption and emission processes allow observation of structure that is normally unobservable. All these unique characters can enormously simplify a complex x-ray spectrum. Applications of this novel technique have generated information from various transition-metal model compounds to metalloproteins. The absorption and emission spectra by high resolution fluorescence detection are interdependent. The ligand field multiplet model has been used for the analysis of K{alpha} and K{beta} emission spectra. First demonstration on different chemical states of Fe compounds has shown the applicability of site selectivity and spin polarization. Different interatomic distances of the same element in different chemical forms have been detected using site-selective EXAFS.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• Sponsoring Organization: USDOE Office of Energy Research (ER); National Inst. of Health
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 456318
• Report Number(s): LBNL--39801; ON: DE97004135; CNN: Contract GM-44380; Contract GM-48145
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CRYSTAL FIELD
MOLECULAR STRUCTURE
SENSITIVITY
SPIN
X-RAY FLUORESCENCE ANALYSIS
X-RAY SPECTROSCOPY