Role of the Crystal Lattice Constants and Band Structures in the Optoelectronic Spectra of CdGa2S4by DFT Approaches

2017 ◽  
Vol 643 (13) ◽  
pp. 839-849 ◽  
Author(s):  
H. A. Rahnamaye Aliabad ◽  
Hamide Vaezi ◽  
Shiva Basirat ◽  
Iftikhar Ahmad
Keyword(s):  
Crystal Lattice ◽  
Band Structures ◽  
Lattice Constants

Crystal structure and lattice energetics of 10-methylacridinium halides

2000 ◽  
Vol 53 (8) ◽  
pp. 627 ◽  
Author(s):  
Piotr Storoniak ◽  
Karol Krzyminski ◽  
Pawel Dokurno ◽  
Antoni Konitz ◽  
Jerzy Blazejowski
Keyword(s):  
Crystal Lattice ◽  
Lattice Energy ◽  
Enthalpies Of Formation ◽  
Triclinic Space Group ◽  
X Ray ◽  
Molecular Arrangement ◽  
Van Der Waals Contacts ◽  
Chloride Monohydrate ◽  
Insight Into

The crystal structures of 10-methylacridinium chloride monohydrate, bromide monohydrate and iodide were determined by X-ray analysis. The compounds crystallize in the triclinic space group, P¯1, with 2 molecules in the unit cell. The molecular arrangement in the crystals revealed that hydrogen bonds (in hydrates) and van der Waals contacts play a significant part in intermolecular interactions. To discover their nature, contributions to the crystal lattice energy arising from electrostatic (the most important since the compounds form ionic crystals), dispersive and repulsive interactions were calculated. Enthalpies of formation of the salts, their stability and susceptibility to decomposition could be predicted from a combination of crystal lattice energies with values of other thermochemical characteristics obtained theoretically or taken from the literature. The role of water in the stabilization of the crystal lattice of the hydrates is also explained. The information gathered has given an insight into the features and behaviour of compounds which can be regarded as models of a large group of aromatic quaternary nitrogen salts.

3d—MAGNETISM OF THE RT4B COMPOUNDS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 798-801
Author(s):  
T.T. DUNG ◽  
N.P. THUY ◽  
T.D. HIEN ◽  
N.M. HONG ◽  
D.C. KHAN ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Cell Volume ◽  
Unit Cell Volume ◽  
Magnetocrystalline Anisotropy ◽  
Close Correlation ◽  
Spin Reorientation ◽  
Lattice Constants ◽  
Spontaneous Magnetostriction ◽  
Relative Value

Spontaneous-magnetostriction and FMR studies are reported for the series Y(CO1−xFex)4B with x=0.00, 0.0125, 0.02 and 0.125. For the samples with composition x=0.00, 0.0125 and 0.02, step-like changes of the lattice constants a and c around the spin reorientation temperature TSR are observed. The relative values of the changes in ∆a/a and ∆c/c are of the order of 10−4 but are of opposite signs. The changes in the unit cell volume ∆V/V around TSR are negligible. In the temperature dependence of the average g-values of these samples, a step-like change with a relative value for ∆g/g of 10−2 has been deduced from FMR studies. These results point to a close correlation between the lattice constants and the magnetocrystalline anisotropy of the 3d-lattice and consequently to the role of the orbital moments in the anisotropic properties of the 3d-magnetism in the considered compounds.

The role of mineral nanoparticles at a fluid-magnetite interface: Implications for trace-element uptake in hydrothermal systems

2019 ◽  
Vol 104 (8) ◽  
pp. 1180-1188 ◽  
Author(s):  
Shuo Yin ◽  
Richard Wirth ◽  
Changqian Ma ◽  
Jiannan Xu
Keyword(s):  
Solid Solution ◽  
Crystal Lattice ◽  
Trace Element ◽  
Hydrothermal Systems ◽  
Oscillatory Zoning ◽  
Bulk Fluid ◽  
Continuous Increase ◽  
Interfacial Fluid ◽  
Spinel Nanoparticles

Abstract The migrating fluid-mineral interface provides an opportunity for the uptake of trace elements as solid solutions in the newly formed crystal lattice during the non-equilibrium growth of the crystal. However, mineral nanoparticles could precipitate directly from the interfacial fluid when it evolves to a supersaturated situation. To better understand the role of mineral nanoparticles in this scenario, this study focuses on a well-documented magnetite with oscillatory zoning from a skarn deposit by using high-resolution transmission electron microscopy (TEM). Our results show that the Al concentration in magnetite measured on a micrometer-scale is caused by three different effects: Al solid solution, Al-rich nanometer-sized lamellae, and zinc spinel nanoparticles in the host magnetite. Here, we propose a genetic relationship among the three different phases mentioned above. At first, a continuous increase of the Al concentration in the interfacial fluid can be incorporated into the crystal lattice of magnetite forming a solid solution. During cooling in a later stage, aluminum in magnetite is oversaturated and exsolution of hercynite (Al-rich lamellae) occurs from the host magnetite. If the Al concentration at the fluid-magnetite interface still increases during further growth of magnetite, the substitution of Fe by Al has gradually reached saturation so that aluminum cannot be incorporated in the magnetite crystal structure any longer. Using the magnetite lattice as a template, nucleation of abundant zinc spinel nanoparticles occurs. This will, in turn, lead to a gradual depletion of Al concentration in the interfacial fluid until the available ions for zinc spinel nucleation and growth have been used up. As a result, the migrating fluid-magnetite interface will enrich the Al concentration in the interfacial fluid until the available ion concentration is sufficient for nucleation of zinc spinel phase again. The fluid-mineral interface in this mechanism has been repeatedly utilized during crystal growth, providing an efficient way for the uptake of trace element from a related undersaturated bulk fluid.

scholarly journals The role of excess Sn in Cu4Sn7S16 for modification of the band structure and a reduction in lattice thermal conductivity

2017 ◽  
Vol 5 (17) ◽  
pp. 4206-4213 ◽  
Author(s):  
Tongtong He ◽  
Naiming Lin ◽  
Zhengliang Du ◽  
Yimin Chao ◽  
Jiaolin Cui
Keyword(s):  
Thermal Conductivity ◽  
Band Structure ◽  
Lattice Thermal Conductivity ◽  
Band Structures

In this work, we have investigated the band structures of ternary Cu4Sn7+xS16 (x = 0–1.0) compounds with an excess of Sn, and examined their thermoelectric (TE) properties.

scholarly journals Mathematical modeling of perspective structures of metal oxides

2020 ◽  
Vol 22 (4) ◽  
pp. 268-271
Author(s):  
P. A. Sechenykh
Keyword(s):  
Metal Oxides ◽  
Crystal Lattice ◽  
Structural Characteristics ◽  
Elementary Cell ◽  
Group Symmetry ◽  
Cubic Symmetry ◽  
Lattice Constants ◽  
General Chemical ◽  
Crystalline Metal ◽  
Chemical Formulas

Information about the structure and properties of materials is especially important when working with micro-and nanoscale objects due to the high complexity of their obtaining. This makes it relevant to use computer modeling to predict the required characteristics of materials. Electronic, magnetic, mechanical, and other properties of crystalline substances are determined by their structure-the periodicity of the lattice and the symmetry of the unit cell. This article discusses metal oxides with the general chemical formulas MeO (metals: Ca, Cd, Mg), MeO2 (metals: Hf, Ce, Zr), Me2O3 (metals: Er, Nd, Sc, Mn, Tl) and Me3O4 (using Fe as an example) and a cubic symmetry type crystal lattice — structural types NaCl (rock salt), Fluorite, Bixbyite, Spinel accordingly. The paper describes the model of ion-atomic radii, which is widely used in the modeling of crystalline metal oxides. The application of the annealing simulation algorithm for calculating the metric parameters of the compounds under consideration is shown. The software implementation of the algorithm presented in this paper allows us to determine the coordinates of the atoms that are included in the elementary cell of the crystal lattice, calculate the lattice constant and the density of the packing of atoms in the crystal cell using the specified chemical formula and the space group symmetry. These structural characteristics can be used as input parameters for determining electronic, magnetic, and other properties. The article compares the values of lattice constants obtained as a result of modeling with experimental data.

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