scholarly journals Derivation of Relation between a parameter of Inverse correlation and effective Charge of X-ray absorbing K-Edge of Copper atom in it’s different Compounds

2020 ◽  
Vol 32 (5) ◽  
pp. 31-35
Author(s):  
RAKESH KUMAR RANJAN ◽  
Keyword(s):  
Numerical Methods ◽  
Copper Atom ◽  
Effective Charge ◽  
Theoretical Basis ◽  
Bond Distance ◽  
Inverse Correlation ◽  
Coordination Bond ◽  
Energy Position ◽  
Catalytic Systems ◽  
X Ray

The article gives an overview of the XANES technique contribution to the analysis of multi-component catalysts. The theoretical basis of the technique, the interpretation of the energy position and intensity of XANES features, and the numerical methods developed to interpret XANES data on catalytic systems are described and discussed. XANES in the K-edge of copper in the systems. CuO, Cu(NO3)2, La2CuO4, CuCl2, and CuBr have been investigated and transitions have been assigned to the observed structures. The measurements have been used for calculating the first coordination bond distance in the above systems. It is observed that the values so determined agree fairly well with crystallographic values

Introduction to molecular simulations in soft matter

2017 ◽  
Author(s):  
J.-L. Barrat ◽  
J. J. de Pablo
Keyword(s):  
Phase Space ◽  
Numerical Methods ◽  
Theoretical Basis ◽  
Soft Matter ◽  
Relevant Literature ◽  
Coarse Grained ◽  
Soft Interfaces ◽  
Molecular Scale ◽  
Soft Matter Physics ◽  
The Continuum

We describe the main features of the coarse-grained models that are typically useful in modelling soft interfaces, from force fields to the continuum descriptions involving density fields. We explain the theoretical basis of the main numerical methods that are used to explore the phase space associated with these models. Finally, three recent examples, illustrating the spirit in which relatively simple simulations can contribute to solving pending problems in soft matter physics, are briefly described. Clearly, a short series of lectures can offer, at best, a biased and restricted view of the available approaches. Our aim here will be to provide the reader with such an overview, with a focus on methods and descriptions that ‘bridge the scale’ between the molecular scale and the continuum or quasi-continuum one. The objective to present a guide to the relevant literature—which has now to a large extent appeared in the form of textbooks.

The Through-Bond Interaction of a Sulfur Lone Pair with Oxygenated Substituents in the Thiacyclohexane Framework

2005 ◽  
Vol 58 (7) ◽  
pp. 531
Author(s):  
Laura Andrau ◽  
Jonathan M. White
Keyword(s):  
Low Temperature ◽  
Crystal Structures ◽  
Bond Distance ◽  
Lone Pair ◽  
X Ray ◽  
Ester Derivative ◽  
Bond Interaction ◽  
Derivatives Of ◽  
Electron Demand

Low-temperature X-ray crystal structures were determined on a range of derivatives of 4-thiacyclohexanol 5a of varying electron demand with a view to finding evidence for a through-bond interaction between the sulfur lone pair and the oxygenated substituent. In contrast to earlier suggestions, plots of C–OR bond distance versus pKa (ROH) showed that any interaction between the sulfur and the OR group is unlikely to be of a through-bond origin. Furthermore, unimolecular solvolysis rate measurements on the nosylate ester derivative 5g showed that the sulfur actually retards the reaction slightly in comparison with the corresponding sulfur-free analogue 6.

The direct electrochemical synthesis of some metal derivatives of lapachol

1997 ◽  
Vol 75 (5) ◽  
pp. 499-506 ◽  
Author(s):  
E.H. De Oliveira ◽  
G.E.A. Medeiros ◽  
C. Peppe ◽  
Martyn A. Brown ◽  
Dennis G. Tuck
Keyword(s):  
Electrochemical Oxidation ◽  
Copper Atom ◽  
Electrochemical Synthesis ◽  
Acetonitrile Solution ◽  
Triclinic Space Group ◽  
X Ray ◽  
Metal Anode ◽  
X Ray Crystallography ◽  
Metal Derivatives ◽  
Derivatives Of

The electrochemical oxidation of a sacrificial metal anode (M = Zn, Cd, Cu) in an acetonitrile solution of 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone, lapachol, C15H14O3 (=HL) gives ML2. The results are in keeping with earlier work on direct electrochemical synthesis in related systems. Adducts with 2,2′-bipyridine (bpy) and N,N,N′,N′-tetramethylethanediamine (tmen) have also been prepared. The structure of the 2,2′-bipyridine adduct of Cu(lapacholate)2 has been established by X-ray crystallography. The parameters are triclinic, space group [Formula: see text], a = 12.748(59) Å, b = 13.859(49) Å, c = 11.770(59) Å, α = 108.30(4)°, β = 108.08(3)°, γ = 68.94(3)°, Z = 2, R = 0.059 for 2256 unique reflections. The copper atom is in a distorted CuN2O2O2′ environment. The mechanism of the formation of this Cu(lapacholate)2 is discussed. Keywords: electrochemical synthesis, lapachol, X-ray crystallography, copper(II) complex.

Comparative Structural Studies on Three-Coordinate Copper(I) Halide Complexes With Tertiary Phosphines. Crystal Structures of [(PPh2Mes)CuX]2 and [(PPhMes2)CuX]2 (Mes = Mesityl X = Cl, Br, I)

1992 ◽  
Vol 45 (7) ◽  
pp. 1155 ◽  
Author(s):  
GA Bowmaker ◽  
D Camp ◽  
RD Hart ◽  
PC Healy ◽  
BW Skelton ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Copper Atom ◽  
Structural Studies ◽  
Coordination Environment ◽  
X Ray ◽  
Tertiary Phosphines ◽  
Structure Determinations ◽  
Halide Complexes ◽  
The Subject

The 1 : 1 complexes of the substituted triphenylphosphine ligands mesityldiphenylphosphine and dimesitylphenylphosphine with copper(1) chloride, bromide and iodide have been the subject of single-crystal X-ray structure determinations at 295 K. All six complexes crystallize as air-stable dimeric molecules, [(PPh2Mes)CuX]2 and [ (PPhMes2)CUX]2 with each copper atom in a distorted trigonal PCuX2. coordination environment. Crystals of [(PPh2Mes)CuCl]2 (1) are monoclinic, P21/n, a 9.961(3), b 18.687(6), c 11.009(7) Ǻ, β 114.63(4)°; R was 0.049 for 2450 'observed' reflections. [(PPh2Mes)CuBrI2 (2) is monoclinic, P21/n, a 9.939(2), b 18.832(6), c 11.238(6) Ǻ, β 115.36(3)°; R was 0.046 for 1803 'observed' reflections. [(PPh2Mes)CuI]2.4/3 C6H6 (3) is rhornbohedral, R3, a 36.877(8), c 9.047(5) A; R was 0.039 for 2537 'observed' reflections. Crystals of [(PPhMes2)CuCl]2.2MeCN (4) are triclinic, Pi, a 15.783(7), b 9.570(4), c 8.914(4) Ǻ, α 72.43(3), β 76.37(3), γ 74.03(3)°; R was 0.045 for 3341 'observed' reflections. [(PPhMes2)CuBr]2.3C6H6 (5) is monoclinic, C2/c, a 9.694(6), b 30.15(2), c 20.66(2) Ǻ, β 98.00(7)°; R was 0.047 for 2117 'observed' reflections. [(PPhMes2)CuI]2.2MeCN (6) is orthorhombic, PP1nb, a 11.694(8), b 14.77(1), c 29.76(3) Ǻ; R was 0.049 for 3447 'observed' reflections. Cu-P bond lengths are: 2.196(2) A (1); 2.198(3) Ǻ (2); 2.222(5) and 2.226(5) Ǻ (3); 2.202(1) Ǻ (4); 2.197(3) A (5); 2.201(4) and 2.264(5) Ǻ (6). The geometries of the LCuX2 and CuX2Cu units are compared with data reported for other monomeric and dimeric compounds for both phosphorus- and nitrogen-based ligands L.

Magnetic and Optical Properties of Eu-doped GaN

2006 ◽  
Vol 955 ◽  
Author(s):  
Jennifer Hite ◽  
G T Thaler ◽  
J H Park ◽  
A J Steckl ◽  
C R Abernathy ◽  
...  
Keyword(s):  
Saturation Magnetization ◽  
Room Temperature Ferromagnetism ◽  
Inverse Correlation ◽  
Absolute Intensity ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
Cell Temperature ◽  
X Ray ◽  
Pl Intensity ◽  
The Eu

ABSTRACTGaN films were doped with Eu to a concentration of ∼0.12 at. % during growth at 800°C by molecular beam epitaxy, with the Eu cell temperature held constant at 470°C. All samples were post-annealed at 675°C. The films exhibited strong photoluminescence (PL) in the red (622 nm) whose absolute intensity was a function of the Ga flux during growth, which ranged from 3-5.4×10−7 Torr. The maximum PL intensity was obtained at a Ga flux of 3.6×10−7 Torr. The samples showed room temperature ferromagnetism with saturation magnetization of ∼0.1-0.45 emu/cm3, consistent with past reports where the Eu was found to be predominantly occupying substitutional Ga sites. There was an inverse correlation between the PL intensity and the saturation magnetization in the films. X-ray diffraction showed the presence of EuGa phases under all of our growth conditions but these cannot account for the observed magnetic properties.

The Effects of Preparation Conditions And Chemical Composition On CMAS Glass Ceramics With One Step Process

2021 ◽  
Author(s):  
Yuliang Guo ◽  
Huixin Jin ◽  
Yuandan Xiao ◽  
Huahao Song ◽  
Shangjiefu Wang
Keyword(s):  
Solid Waste ◽  
Theoretical Basis ◽  
Chromium Content ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Crystallization Activation Energy ◽  
X Ray ◽  
Preparation Conditions ◽  
Treatment Conditions ◽  
One Step

Abstract Based on the composition of Cr-doped solid waste, other oxides were added to adjust the composition to prepare glass-ceramics with on step composition, and the effect of heat treatment system (including temperature and holding time), chromium content, MnO and Fe2O3 doped on the crystallization and physical properties of glass-ceramics was studied. The samples were characterized by X-ray diffraction, differential thermal analysis and scanning electron microscopy. The results show that the best treatment conditions are 1090 ℃ for 4h, and the amount of dissolved chromium reaches 5%. The main crystallization phase is diopside and anorthite. The hardness and chemical stability of the material were measured. The doping of MnO and Fe2O3 increases the crystallization activation energy of glass ceramics, and makes the crystal phase more uniform as the SEM results. This experiment provides a theoretical basis for the preparation of CMAS glass ceramics from chromium containing solid waste.

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