scholarly journals XAFS spectroscopy by an X-ray tube based spectrometer using a novel type of HOPG mosaic crystal and optimized image processing

2015 ◽  
Vol 30 (5) ◽  
pp. 1080-1085 ◽  
Author(s):  
C. Schlesiger ◽  
L. Anklamm ◽  
H. Stiel ◽  
W. Malzer ◽  
B. Kanngießer
Keyword(s):  
Image Processing ◽  
Chemical Species ◽  
X Ray ◽  
Xafs Spectroscopy ◽  
Bond Lengths ◽  
Mosaic Crystal

This paper presents a XAFS laboratory spectrometer with optimized image treatment suitable for determination of bond lengths and chemical species.

Determination of bond lengths in some compounds of rhenium from the x-ray LIII absorption discontinuity

Pramana ◽  
1973 ◽  
Vol 1 (2) ◽  
pp. 104-108 ◽  
Author(s):  
A V Pendharkar ◽  
Chintamani Mande
Keyword(s):  
X Ray ◽  
Bond Lengths

Intraionic Structure of HS04- and Alkali Cation Configuration in Molten NaHS04 and KHS04

1994 ◽  
Vol 49 (7-8) ◽  
pp. 785-789 ◽  
Author(s):  
K. Fukushima ◽  
M. Murofushi ◽  
M . Oki ◽  
K. Igarashi ◽  
J. Mochinaga ◽  
...  
Keyword(s):  
Molten Salts ◽  
Molecular Orbital Calculations ◽  
Distorted Tetrahedron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths ◽  
Semi Empirical ◽  
Polyatomic Anion ◽  
Short Range Structure

Abstract The short range structure of molten NaHSO4(I) and KHSO4(II) was estimated by X-ray diffraction. The polyatomic anion, HSO4-, in both molten salts was found to have a distorted tetrahedral structure in which the bond lengths of S-O and S-OH were 1.45 Å and 1.53 Å in (I) and 1.46 Å and 1.56 Å in (II), respectively. The coordination number of the Na+ or K+ around the HSO4- was evaluated to be about unity. The semi-empirical molecular orbital calculations by the MNDO-MOPAC method were applied to the determination of the intraionic structure of the H S 0 4 and the bond lengths of S-O and S -OH were computed to be 1.528 Å and 1.666 Å, respectively, supporting qualitatively that the HSO4- forms a rather distorted tetrahedron.

Separation of Effects due to Superimposition Using the Rietveld Method in Spectra Obtained by WDXRF

2006 ◽  
Vol 530-531 ◽  
pp. 59-64
Author(s):  
V.L.R. Salvador ◽  
Nelson Batista de Lima
Keyword(s):  
Rietveld Method ◽  
Chemical Species ◽  
Surface Preparation ◽  
Chemical Separation ◽  
Electronic Transitions ◽  
Critical Stage ◽  
X Ray ◽  
Standard Specimens ◽  
Valence Electrons

This paper presents a new method to separate interfering spectra obtained in wavelength dispersive x-ray fluorescence spectrometry (WDXRF). This method permits improved results to be obtained, compared to conventional analytical results and enables the determination of chemical species of the same element without chemical separation. This is done by separation of the spectra due to electronic transitions of the valence electrons. The Rietveld method [11] overcomes the problem of superimposed peaks of the species present in the specimen and simultaneously enables determination of the species and does not require standard specimens and calibration curves. This signifies a marked improvement in comparison to other techniques. Specimen surface preparation to obtain spectra is a critical stage and its effects can be minimized by using Rietveld refinement, which permits the determination of intensity relationships of superimposed peaks with the aid of mathematical models. This establishes the basic conditions to obtain more accurate results in quantitative analysis. In the determination of chemical species, it is possible to separate, for example, Cr (III) and Cr (IV), with almost 100% superimposition.

Synthesis and X-ray structure determination of the Ir–Ag–Ir donor–acceptor metal–metal bonded complex [{(η5-C5Me5)(CO)2Ir}2Ag][BF4]

1989 ◽  
Vol 67 (11) ◽  
pp. 1832-1836 ◽  
Author(s):  
Frederick W. B. Einstein ◽  
Richard H. Jones ◽  
Xiaoheng Zhang ◽  
Derek Sutton
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Title Complex ◽  
Monoclinic Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Metal Metal ◽  
Donor Acceptor ◽  
Silver Metal

The title complex (2) has been synthesized from the reaction of (η5-C5Me5)Ir(CO)2 (1) with AgBF4. Complex 2 crystallizes in the monoclinic space group P21/c with a = 12.355(2) Å, b = 13.713(2) Å, c = 16.672(3) Å, β = 97.70(1)°, and Z = 4. The structure was solved by using 3131 observed reflections (I ≥ 2.5σ(I)) in the range 0° < 2θ < 50° to final discrepancy indices of RF = 0.032 and RwF = 0.038. The cation may be described as consisting of two molecules of 1 bound to Ag+ by donor–acceptor Ir → Ag bonds. The Ir—Ag—Ir skeleton is nearly linear (angle 173.67(6)°). The Ag—Ir bond lengths are equal (2.659(1) Å), and the two molecules of 1 are disposed mutually trans, to give the cation approximate (noncrystallographic) C2h symmetry. Keywords: complex, iridium, silver, metal-metal bond, X-ray, crystal, structure, carbonyl, donor-acceptor, pentamethylcyclopentadienyl.

Sign in / Sign up

Export Citation Format

Share Document