Soft X-Ray Absorption Microscopy of Surfaces with Synchrotron Radiation

1988 ◽  
Vol 143 ◽  
Author(s):  
G. R. Harp ◽  
B. P. Tonner
Keyword(s):  
Synchrotron Radiation ◽  
Sample Surface ◽  
Spectroscopic Technique ◽  
Solid Surfaces ◽  
Chemical Information ◽  
Secondary Electrons ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

AbstractAs a spectroscopic technique, x-ray absorption near-edge structure (XANES) of core-levels using synchrotron radiation is in wide-spread use for the determination of the molecular composition of solid surfaces. A common detection method measures the yield of secondary electrons, which is proportional to the x-ray absorption coefficient for sufficiently high photon energy. In the experiments reported here, we show how the secondary electrons emitted as a result of photoabsorption can be used to generate a magnified image of the sample surface, with fundamental spatial limits determined by the deBroglie wavelength of the emitted electrons. Contrast in the secondary electron spatial distribution contains both topographical and chemical information about the sample surface. The use of tunable synchrotron radiation enables us to separate these contributions to the microscopic image, and to spatially resolve surface chemical composition as reflected in micro-XANES spectra.

Determination of Bond Lengths and Electronic Structure of Cd1-xZnxTe Ternary Alloys by Synchrotron Radiation

2013 ◽  
Vol 706-708 ◽  
pp. 56-59 ◽  
Author(s):  
Wei Zheng ◽  
Yu Li Wu ◽  
Yen Ting Chen ◽  
Zhe Chuan Feng ◽  
Jyh Fu Lee ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Fine Structure ◽  
Synchrotron Radiation ◽  
Electronic Structures ◽  
Ternary Alloys ◽  
Chemical Bonds ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

High-resolution synchrotron radiation x-ray absorption spectroscopy on Zn K-, Cd L3- and Te L3-edges for Cd1-xZnxTe ternary alloys with x = 0.10, 0.30, 0.50 and 0.90 are presented. A detailed analysis of the extended x-ray absorption fine structure using the IFEFFIT program, and the chemical bonds of Zn-Te are obtained, suggesting distortion of the Te sub-lattice. The x-ray absorption near-edge structure of the Zn K-, Cd L3- and Te L3-edge are investigated, and the electronic structures of Cd1-xZnxTe with various compositions are studied.

X-ray absorption spectroscopy studies for the determination of adsorption binding modes of selenium oxoanions onto iron and manganese based nanomaterials

2012 ◽  
Vol 1480 ◽  
Author(s):  
Christina M. Gonzalez ◽  
Jason G. Parsons ◽  
Jeffrey Hernandez ◽  
Jorge L. Gardea-Torresdey
Keyword(s):  
Absorption Spectroscopy ◽  
Binding Modes ◽  
Edge Structure ◽  
X Ray ◽  
Microwave Assisted ◽  
Spectroscopy Studies ◽  
X Ray Absorption ◽  
Binding Mechanisms ◽  
Iron And Manganese

ABSTRACTIncreasing concentrations of selenium oxoanions in the environment are placing many animals at risk for reproduction failure and deformities. The understanding of binding mechanisms of selenium oxoanions to iron and manganese based oxide minerals could lead to enhanced understanding of selenium mobility in the environment. In this study, the binding mechanisms of selenium oxoanions, selenite and selenate, to non microwave-assisted and microwave-assisted synthetic Fe3O4, Mn3O4, and MnFe2O4 nanomaterials were investigated through the use of X-ray absorption spectroscopy. The X-ray absorption near-edge structure (XANES) spectroscopy studies revealed the oxidation state of selenite and selenate remains the same after binding occurs to all nanomaterials in pH 2, 4, or 6 environments. The binding modes of selenite and selenate were determined to be bidentate binuclear through use of Extended x-ray absorption fine structure (EXAFS) and were independent of nanomaterials, synthetic technique, and pH.

Eyeing the past: synchrotron µ-XANES and XRF imaging of tarnish distribution on 19th century daguerreotypes

2019 ◽  
Vol 26 (5) ◽  
pp. 1679-1686 ◽  
Author(s):  
M. S. Kozachuk ◽  
T. K. Sham ◽  
R. R. Martin ◽  
A. J. Nelson ◽  
I. Coulthard
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Synchrotron Radiation ◽  
National Gallery ◽  
Edge Structure ◽  
X Ray ◽  
The Past ◽  
National Gallery Of Canada ◽  
X Ray Absorption ◽  
Scanning Electron

Louis-Jacques-Mandé Daguerre introduced the first successful photographic process, the daguerreotype, in 1839. Tarnished regions on daguerreotypes supplied by the National Gallery of Canada were examined using scanning electron microscopy energy-dispersive X-ray spectroscopy and synchrotron-radiation analysis. Synchrotron X-ray fluorescence imaging visualized the distribution of sulfur and chlorine, two primary tarnish contributors, and showed that they were associated with the distribution of image particles on the surface. X-ray absorption near-edge structure spectroscopy determined the tarnish to be primarily composed of AgCl and Ag2S. Au2S, Au2SO4, HAuCl4 and HgSO4 were also observed to be minor contributors. Environmental contamination may be a source of these degradation compounds. Implications of these findings will be discussed.

X-RAY PHOTOEMISSION ELECTRON MICROSCOPE DETERMINATION OF ORIGINS OF ROOM TEMPERATURE FERROMAGNETISM AND PHOTOLUMINESCENCE IN HIGH Co-CONTENT CoxZn1-xO FILMS

2014 ◽  
Vol 21 (04) ◽  
pp. 1450058 ◽  
Author(s):  
WEI CAO ◽  
VLADIMIR PANKRATOV ◽  
MARKO HUTTULA ◽  
LIANA SHIRMANE ◽  
YU RAN NIU ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Luminescence Properties ◽  
Edge Structure ◽  
X Ray ◽  
Zno Nanoclusters ◽  
X Ray Absorption ◽  
Photoemission Electron

In this paper, we reported on the X-ray photoemission electron microscope (XPEEM) determination of magnetic and luminescence origins for two Co x Zn 1-x O films. The cobalt fraction x of radio frequency co-sputtered samples were 0.86(2) and 0.92(2), respectively. Films were ferromagnetic and semiconductive. Unique narrow green color lines beside the ZnO intrinsic emissions were found with a decay time in microsecond range at room temperature. Origins of magnetic and luminescence properties were determined with XPEEM. The X-ray absorption near edge structure at the Co  L3-edge denoted that Co was partially oxidized, and phase-contrast images together with chemical composition identification further proved that Co and CoO co-existed in the samples. The ferromagnetism was attributed to ferromagnetism of Co clusters partially canceled by the antiferromagnetism of its oxide, and the photoluminescence to bound exciton in ZnO nanoclusters and defect related centers of ZnO nanoclusters in a Co -rich matrix. Present results show possibilities for adjusting magnetic and luminescence properties of Co – ZnO compounds by changing the cobalt concentration.

Direct determination of oxidation state of gold deposits in metal-reducing bacterium Shewanella algae using X-ray absorption near-edge structure spectroscopy (XANES)

2007 ◽  
Vol 103 (6) ◽  
pp. 568-571 ◽  
Author(s):  
Yasuhiro Konishi ◽  
Takeshi Tsukiyama ◽  
Norizoh Saitoh ◽  
Toshiyuki Nomura ◽  
Shinsuke Nagamine ◽  
...  
Keyword(s):  
Oxidation State ◽  
Direct Determination ◽  
Gold Deposits ◽  
Edge Structure ◽  
X Ray ◽  
Shewanella Algae ◽  
X Ray Absorption

Direct determination of Mn occupations in Ga1−xMnxN dilute magnetic semiconductors by x-ray absorption near-edge structure spectroscopy

2006 ◽  
Vol 89 (12) ◽  
pp. 121901 ◽  
Author(s):  
Shiqiang Wei ◽  
Wensheng Yan ◽  
Zhihu Sun ◽  
Qinghua Liu ◽  
Wenjie Zhong ◽  
...  
Keyword(s):  
Magnetic Semiconductors ◽  
Dilute Magnetic Semiconductors ◽  
Direct Determination ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption
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