Coordination structures of implanted Fe, Co, and Ni ions in silica glass by x-ray absorption fine structure spectroscopy

2001 ◽  
Vol 16 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Kohei Fukumi ◽  
Akiyoshi Chayahara ◽  
Kohei Kadono ◽  
Hiroyuki Kageyama ◽  
Tomoko Akai ◽  
...  
Keyword(s):  
Fine Structure ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Glass Matrix ◽  
Optical Absorption Spectra ◽  
Tetrahedral Symmetry ◽  
Interatomic Distances ◽  
X Ray ◽  
Silica Glasses ◽  
X Ray Absorption

Coordination structures of implanted Fe, Co, and Ni ions were studied in 1.78–2.00-MeV 5 × 1016 ions/cm2-implanted silica glasses by x-ray absorption and optical absorption spectroscopies. It was found from x-ray absorption spectra that the implanted Fe, Co, and Ni ions are coordinated by ca.3 oxygen atoms. The implanted ions dispersed in glass matrix and did not form crystals. The valence of the implanted ions was about 1.5. The Fe–O, Co–O, and Ni–O interatomic distances were 190, 191, and 192 pm, respectively. In addition, it was found from optical absorption spectra that one-fifth of implanted Co ions were present as Co2+ ions in tetrahedral symmetry.

X-Ray Absorption Spectroscopic Studies of Catalytic Materials

1988 ◽  
Vol 143 ◽  
Author(s):  
G. H. Via ◽  
J. H. Sinfelt ◽  
G. Meitzner ◽  
F. W. Lytle
Keyword(s):  
Fine Structure ◽  
Physical Environment ◽  
Bimetallic Catalysts ◽  
Spectroscopic Studies ◽  
Interatomic Distances ◽  
X Ray ◽  
Coordination Numbers ◽  
Supported Platinum ◽  
High Fraction ◽  
X Ray Absorption

AbstractX-ray absorption spectra (XAS) contain information in the LIII near-edge region on filling of the absorber d-band, and in the extended fine-structure region on the physical environment of the absorber. We report here an evaluation of the effect on platinum LIII edges of preparation in clusters with a high fraction of Pt atoms at the surface. We also report the effects on platinum and rhenium LIII edges from addition of copper. These effects are surprisingly small.We have also re-evaluated extended x-ray absorption fine-structure spectra (EXAFS) of platinum and rhenium in alumina-supported platinum-rhenium bimetallic catalysts. A novel feature of this new analysis was the requirement that interatomic distances, coordination numbers, and Debye-Waller type factors maintain certain physically necessary relationships among themselves. This procedure decreased the number of free variables and increased the amount of information returned by the analysis.

X-Ray Absorption Fine Structure Study in FeTiO3

1997 ◽  
Vol 11 (16n17) ◽  
pp. 745-748 ◽  
Author(s):  
Rebekah Min-Fang Hsu ◽  
Kai-Jan Lin ◽  
Cheng Tien ◽  
Lin-Yan Jang
Keyword(s):  
Absorption Spectrum ◽  
Fine Structure ◽  
Absorption Spectra ◽  
Mixed Valence ◽  
Structure Study ◽  
X Ray ◽  
Xafs Spectroscopy ◽  
Absorption Fine ◽  
Trivalent State ◽  
X Ray Absorption

X-ray absorption fine structure XAFS spectroscopy has been used to determine the valence system for the Fe atom in ilmenite, FeTiO3 . This is the first XAFS data in FeTiO3 to our knowledge. The α- Fe2O3 data served as the standard in determining the ionization of the Fe atom in FeTiO3 . Observation of intensity and k-space are consistent. There was no evidence of mixed valence on comparing the FeTiO3 near edge X-ray absorption spectrum with α- Fe2O3 data. The absorption spectra suggest that iron is in the trivalent state in ilmenite.

Extended Fine Structure in X-Ray Absorption Spectra of Certain Perovskites

1970 ◽  
Vol 2 (5) ◽  
pp. 1317-1323 ◽  
Author(s):  
Joseph Perel ◽  
Richard D. Deslattes
Keyword(s):  
Fine Structure ◽  
Absorption Spectra ◽  
X Ray ◽  
X Ray Absorption

scholarly journals Optical Studies on KBr:Tl and KCl-Br:Tl Mixed Crystals

2010 ◽  
Vol 7 (2) ◽  
pp. 425-432
Author(s):  
P. Eswaran ◽  
A. Anbagi ◽  
S. Nagarajan
Keyword(s):  
Optical Absorption ◽  
Single Crystals ◽  
Absorption Spectra ◽  
Emission Band ◽  
Mixed Crystals ◽  
Optical Absorption Spectra ◽  
Optical Studies ◽  
Excitation Spectra ◽  
X Ray ◽  
Wavelength Side

Optical absorption spectra of KBr:Tl+(0.0125 mol%) single crystals shows A, B and C bands around 258, 220 and 210 nm respectively. In KCl0.1Br0.9:Tl+(0.0125 mol%) mixed crystals exhibit slightly broadening of the A-band towards lower wavelength side. The broadening of the absorption spectra are suggested to be due to some complex Tl+centers involving Br-and Cl-ions formed in the mixed crystals. When excited at A, B and C-bands of Tl+ions, PL of KBr:Tl+showed emission band around 320 with a prominent shoulder around 365 nm. In KCl0.1Br0.9mixed crystals the shoulder around 365 nm is not prominent due to the perturbing influence of Cl-ions. Addition bands in the excitation spectra are attributed to the presence of Tl+dimmers. PSL observed in X-ray irradiated crystals resembled their respective PL emissions indicating that PSL in them is due to Tl+ions.

The role of dysprosium ions on the physical and optical properties of lithium-borosulfophosphate glasses

2017 ◽  
Vol 31 (13) ◽  
pp. 1750101 ◽  
Author(s):  
Ibrahim Bulus ◽  
S. A. Dalhatu ◽  
R. Hussin ◽  
W. N. Wan Shamsuri ◽  
Y. A. Yamusa
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Physical Parameters ◽  
Potential Candidate ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
X Ray ◽  
Nir Absorption ◽  
Optical Applications

Achieving outstanding physical and optical properties of borosulfophosphate glasses via controlled doping of rare earth ions is the key issue in the fabrication of new and highly-efficient glass material for diverse optical applications. Thus, the effect of replacing P2O5 by Dy2O3 on the physical and optical properties of Dy[Formula: see text]-doped lithium-borosulfophosphate glasses with chemical composition of 15Li2O–30B2O3–15SO3–[Formula: see text]P2O5–[Formula: see text]Dy2O3 (where 0.0 mol.% [Formula: see text] mol.%) has been investigated. The glass samples were synthesized from high-purity raw materials via convectional melt-quenching technique and characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectrometry (EDX), density and UV–vis–NIR absorption measurements. The amorphous nature of the prepared glass samples was confirmed by XRD patterns whereas the EDX spectrum depicts elemental traces of O, C, B, S, P and Dy. The physical parameters such as density, refractive index, molar volume, polaron radius and field strength were found to vary nonlinearly with increasing Dy2O3 concentration. UV–vis–NIR absorption spectra revealed seven absorption bands with most dominant peak at 1269 nm (6H[Formula: see text]F[Formula: see text]H[Formula: see text]). From the optical absorption spectra, the optical bandgap and Urbach’s energy have been determined and are related with the structural changes occurring in these glasses with increase in Dy2O3 content. Meanwhile, the bonding parameters ([Formula: see text]) evaluated from the optical absorption spectra were found to be ionic in nature. The superior features exhibited by the current glasses nominate them as potential candidate for nonlinear optical applications.

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