Theoretical investigations of 63Cu2+ orbital Knight shifts for YBa2Cu4O8

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542007 ◽  
Author(s):  
Min-Quan Kuang ◽  
Shao-Yi Wu ◽  
Zhi-Hong Zhang ◽  
Xian-Fen Hu
Keyword(s):  
Experimental Data ◽  
Experimental Verification ◽  
High Order ◽  
Order Perturbation ◽  
Theoretical Investigations ◽  
Calculation Results ◽  
Knight Shifts ◽  
Good Agreement

The temperature-independent orbital Knight shifts for the orthorhombic [Formula: see text] site in [Formula: see text] (Y124) are investigated by utilizing the high order perturbation formulae of these parameters for a [Formula: see text] ion situated into orthorhombically elongated octahedra. The calculation results are in good agreement with the experimental data. The moderate quasi-axial anisotropies of the Knight shifts are ascribed to the elongation distortion of the four-fold coordinated Cu[Formula: see text] site. The [Formula: see text] factors are also theoretically calculated in a uniform way for further experimental verification.

Studies of Knight Shifts and Hyperfine Structure Constants of Tl2Ba2CuO6+y

2013 ◽  
Vol 337-338 ◽  
pp. 49-53
Author(s):  
Min Quan Kuang ◽  
Shao Yi Wu ◽  
Xian Fen Hu ◽  
Bo Tao Song
Keyword(s):  
Hyperfine Structure ◽  
Local Structure ◽  
High Order ◽  
Order Perturbation ◽  
Calculation Results ◽  
Structure Constants ◽  
Knight Shifts ◽  
Good Agreement

The Knight shifts and hyperfine structure constants of Tl2Ba2CuO6+yare theoretically studied from the high order perturbation formulas of these quantities for a tetragonally elongated octahedral 3d9cluster. The calculation results reveal good agreement with the observed values. The obvious anisotropies of the Knight shifts can be ascribed to the local tetragonal elongation of the Cu2+site. The results and the local structure of the system are discussed.

Theoretical Investigations of the Knight Shifts and the Hyperfine Structure Constants for the Tetragonal Cu2+ Sites in the Bismuth- and Thallium-Based High-Tc Superconductors

2013 ◽  
Vol 68 (6-7) ◽  
pp. 442-446 ◽  
Author(s):  
Min-Quan Kuang ◽  
Shao-Yi Wu ◽  
Xian-Fen Hu ◽  
Bo-Tao Song
Keyword(s):  
Hyperfine Structure ◽  
High Tc Superconductors ◽  
Paramagnetic Resonance ◽  
High Tc ◽  
Theoretical Investigations ◽  
Calculation Results ◽  
Structure Constants ◽  
Knight Shifts ◽  
Electron Paramagnetic ◽  
Good Agreement

The Knight shifts and hyperfine structure constants for the tetragonal Cu2+ sites in bismuth- and thallium-based high-Tc uperconductors ( Bi1:6Pb0:4Sr2Ca2Cu3O10, TlSr2CaCu2O7-y, and Tl2Ba2CuOy) are theoretically investigated from the high-order perturbation formulas of these parameters for a 3d9 ion under tetragonally elongated octahedra in a unified way. The calculation results show good agreement with the observed values. The significant anisotropies of the Knight shifts are attributed to the local tetragonal elongation distortions of the five-(or six-)coordinated Cu2+ sites in these systems. The present studies would be beneficial to establish a complete physical scheme for unified understandings of electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectral behaviours of Cu2+ (or other similar 3d9 ions) in the high-Tc superconductors.

Theoretical studies on the Knight shifts for the tetragonal Cu2+ site in HgBa2CuO4+δ

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542020
Author(s):  
Guo-Liang Li ◽  
Shao-Yi Wu ◽  
Min-Quan Kuang ◽  
Xian-Fen Hu
Keyword(s):  
Local Structure ◽  
High Order ◽  
Order Perturbation ◽  
Theoretical Studies ◽  
Copper Site ◽  
Calculation Results ◽  
Knight Shifts

The Knight shifts for the tetragonal [Formula: see text] site in [Formula: see text] are theoretically studied from the high order perturbation formulas of the Knight shifts for a tetragonally elongated octahedral [Formula: see text] cluster. The significant anisotropy of the Knight shifts is attributable to the obvious tetragonal elongation distortion of the [Formula: see text] site. The anisotropic [Formula: see text] factors of this system are uniformly analyzed, and the calculation results and the local structure of the copper site are also discussed.

Simulation on Coal Devolatilization Combined a Multi-Step Kinetic Model with Chemkin Software

2012 ◽  
Vol 608-609 ◽  
pp. 1375-1382
Author(s):  
Rui Zhang ◽  
Qin Hui Wang ◽  
Zhong Yang Luo ◽  
Meng Xiang Fang
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Intermediate Product ◽  
Coal Combustion ◽  
Model Complexity ◽  
Coal Pyrolysis ◽  
Simple Application ◽  
Calculation Results ◽  
Simulation Results ◽  
Good Agreement

As the first step in coal combustion and gasification, coal devolatilization has significant effect on reaction process. Previous coal devolatilization models have some disadvantages, such as poor flexibility, model complexity, and requirement of characterization parameters. Recently, Sommariva et al. have proposed a multi-step kinetic model of coal devolatilization. This model avoids the disadvantages mentioned above and can predict elemental composition of tar and char. In this paper, the mechanism of this model has been revised for simple application to Chemkin. Revision method is that some reactions are split into more reactions by using one pseudo-intermediate-product to replace several final products. Simulation results show that calculation results from revised mechanism compare quite well with that from original mechanism and have good agreement with experimental data. The revised mechanism is accurate and can be applied to Chemkin very easily, which gives it wide application to simulation of coal pyrolysis, gasification and combustion.

Pemuatan listrik bipolar untuk partikel aerosol

2018 ◽  
Vol 4 (3) ◽  
pp. 287
Author(s):  
Heru Setyawan
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Ion Mobility ◽  
Opposite Sign ◽  
Aerosol Particles ◽  
Calculation Results ◽  
Two Parameters ◽  
Diffusion Charging ◽  
Fuchs Theory ◽  
Good Agreement

Bipolar diffusion charging of aerosol particles has been studied theoretically using Fuchs theory. Experimental data measured by several researchers available in the published literature were used to verify the calculation results. The calculation results show that Fuchs theory has been successfully used to predict the experimental data of the charging probability of submicron aerosol particles. The combination probability of ion-particle increases with the increase of particle size, both for particle and ion with the same sign and those with the opposite sign. However the combination probability is larger if the charges of particle and ion are of the opposite sign. Generally, Fuchs theory is not too easy to deal with due to the ill-defined of all parameters used, namely ion mass and ion mobility. These cause many possibilities of parameter combination that can give a good agreement with experimental data. Thus, in order to interpret the experimental results properly, the two parameters should be measured simultaneously with aerosol measurements.Keywords: Aerosol, Bipolar Charging, Combination ProbabilityAbstrakPemuatan listrik difusi bipolar partikel aerosol telah dipelajari secara teoritis menggunakan teori Fuchs. Sebagai verifikasi digunakan data eksperimen beberapa peneliti yang tersedia dalam literatur yang telah dipublikasikan. Hasil perhitungan menunjukkan bahwa teori Fuchs berhasil memprediksi dengan baik data eksperimen probabilitas pemuatan listrik partikel aerosol dalam rentang ukuran partikel berukuran submikron. Probabilitas penggabungan ion-partikel semakin besar dengan semakin besarnya ukuran partikel, baik untuk partikel dan ion yang memiliki tanda yang berlawanan maupun yang memiliki tanda yang sama. Akan tetapi, probabilitas penggabungan untuk partikel dan ion yang memiliki tanda yang berlawanan memiliki nilai yang lebih besar. Pada umumnya teori Fuchs tidak terlalu mudah untuk digunakan yang disebabkan oleh tidak terdefinisikannya dengan baik semua parameter yang digunakan, yaitu  massa ion dan mobilitas ion. Hal ini mengakibatkan banyak kemungkinan kombinasi parameter yang bisa menghasilkan kesesuaian yang bagus dengan data hasil pengukuran. Jadi, agar dapat menginterpretasikan hasil pengukuran dengan tepat, kedua besaran tersebut harus diukur secara serempak denganpengukuran aerosol.Kata Kunci: Aerosol, Pemuatan Listrik Bipolar, Probabilitas Penggabungan

Experimental and theoretical investigations of optical properties of GaN/AlGaN MQW nanostructures. Impact of built-in polarization fields

2009 ◽  
Vol 17 (4) ◽  
Author(s):  
M. Esmaeili ◽  
M. Gholami ◽  
H. Haratizadeh ◽  
B. Monemar ◽  
P. Holtz ◽  
...  
Keyword(s):  
Experimental Data ◽  
Quantum Wells ◽  
Electric Fields ◽  
Heavy Hole ◽  
Multiple Quantum ◽  
Interface Charges ◽  
Peak Energy ◽  
Theoretical Investigations ◽  
Electron Ground State ◽  
Good Agreement

AbstractWe report the results from detailed optical spectroscopy from MOCVD grown GaN/AlGaN multiple quantum wells (MQWs), as opposed to most previous studies where MBE was employed by means of photoluminescence (PL) technique. In this paper we will present theoretical and experimental results demonstrating how polarization induced electric fields and bound interface charges in GaN/AlGaN MQWs affect the emission peak energy, PL line shape, as well as the emission line width. Theoretically estimated fields in this work are consistent with experimental data. Transition energy of the heavy hole and electron ground state Ee-hh in GaN/AlGaN MQWs were calculated and it is found that it stays in good agreement with the experimental data.

Prediction of Solid-Liquid Interface Stability and Dendritic Growth in Multi-Component Alloys with Calphad Method

2005 ◽  
Vol 475-479 ◽  
pp. 2721-2724
Author(s):  
Rui Jie Zhang ◽  
Zhi He ◽  
Wan Qi Jie
Keyword(s):  
Experimental Data ◽  
Present Method ◽  
Dendritic Growth ◽  
Calphad Method ◽  
Liquid Interface ◽  
Interface Stability ◽  
Calculation Results ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Good Agreement

A method to predict the solid-liquid interface stability and the constrained dendrite growth of multi-component alloys was developed based on the Calphad method. The method was applied to several industrial Al-Si-Mg alloys, and the predicted results were compared with some former experimental data. The good agreement between the calculation results and the experimental data demonstrates the superiority of the present method to the classical one based on constant parameter assumptions.

High-Pressure Elastic Constant of Some Materials of Earth’s Mantle

2016 ◽  
Vol 71 (5) ◽  
pp. 433-437
Author(s):  
Quan Liu
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Theoretical Model ◽  
Elastic Behaviour ◽  
Exponential Relationship ◽  
Earth’S Mantle ◽  
Simple Theoretical Model ◽  
Volume Dependence ◽  
Theoretical Investigations ◽  
Good Agreement

AbstractIn the present work, an exponential relationship for the volume dependence of the Anderson–Grüneisen parameter along isotherm and the formulation derived from Tallon’s model have been used to develop a simple theoretical model for the elastic constants as a function of pressure. Applying it to some materials of earth’s mantle at different pressure ranges, the calculated results are in good agreement with the earlier theoretical investigations and available experimental data and thus show that our theory can be applied for predicting the elastic behaviour of earth materials at high pressure.

Theoretical investigations of the g factors of orthorhombic Cu2+ site in oxycarbonate phase YBa2Cu2.95(CO3)0.35O6.6

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542016 ◽  
Author(s):  
Yong-Qiang Xu ◽  
Shao-Yi Wu ◽  
Zhi-Hong Zhang ◽  
Hui-Ning Dong
Keyword(s):  
Experimental Data ◽  
Structural Parameters ◽  
Theoretical Formula ◽  
Length Variation ◽  
Apical Oxygen ◽  
Oxygen Ions ◽  
Theoretical Investigations ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Good Agreement

The [Formula: see text] factors of orthorhombic [Formula: see text] site in oxycarbonate phase [Formula: see text] are theoretically investigated using the perturbation formulas of the [Formula: see text] factors for an orthorhombically elongated [Formula: see text] cluster. This pseudo-octahedral [Formula: see text] center is formed by two apical oxygen ligands and four coplanar oxygen ions belonging to the respective four neighboring carbonate groups. The [Formula: see text] cluster is found to suffer the relative axial elongation of about 0.04 Å and the perpendicular bond length variation of about 0.12 Å due to the Jahn–Teller effect. The theoretical [Formula: see text] factors based on the local structural parameters show good agreement with the experimental data.

scholarly journals Effet of edge fluorination and chlorination on structures, stability, electronic and charge transport properties of benzo[o]bistriphenyleno[2,1,12,11-efghi:2',1',12',11'-uvabc]ovalene molecule : DFT study.

2021 ◽  
Author(s):  
Marius Ousmanou Bouba ◽  
Fridolin Tchangnwa Nya ◽  
Christine Yvette Ngui ◽  
Jean Marie Ndjaka
Keyword(s):  
Experimental Data ◽  
Density Functional ◽  
Charge Carriers ◽  
Bandgap Energy ◽  
Electron Affinities ◽  
New Materials ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Theoretical Investigations ◽  
Good Agreement

Abstract We have investigated the structures, electronic properties, hole and electron mobilities of fluorinated and chlorinated nanographene of benzo[o]bistriphenyleno[2,1,12,11-efghi:2',1',12',11'-uvabc]ovalene (TCHG) molecules, us- ing the density functional theory (DFT) and Markus-Hush charge transfer theory. The calculated geometric parameters and the IR spectrum for chlorinated TCHG are in good agreement with the experimental data. Our theoretical investigations have shown that fluorination and chlorination significantly reduce the bandgap energy of TCHG. The obtained adiabatic electron affinities (AEAs) values are 2.76 and 2.93 eV respectively, indicating the air-stable materials. The calculation of charge carriers mobilities in chlorinated dimer shows that the mobility of the electrons is ten times that of the holes, suggesting an n-type behavior. We have shown that the fluorination and chlorination of TCHG are promising pathways for the design of new materials useful in optoelectronics

Sign in / Sign up

Export Citation Format

Share Document