Calculations and Experimental Studies of TAGzT under High Pressure

MRS Advances ◽  
2016 ◽  
Vol 1 (17) ◽  
pp. 1227-1232
Author(s):  
I.G. Batyrev ◽  
R.C. Sausa
Keyword(s):  
High Pressure ◽  
Perturbation Theory ◽  
Density Functional ◽  
Ambient Pressure ◽  
Experimental Studies ◽  
Vibrational Modes ◽  
Density Functional Perturbation Theory ◽  
Potential Formalism ◽  
Pseudo Potential ◽  
Raman And Ir Spectroscopy

ABSTRACTWe studied TAGzT theoretically using density functional perturbation theory within the plane-wave-pseudo-potential formalism and experimentally by Raman and IR spectroscopy at ambient and high pressure. The modeled spectra predict reasonably well the experimental spectra at ambient pressure and the Raman vibrational modes at pressures up to 25 GPa. We report the effects of pressure on volume, Raman and IR vibrational modes, and charge distribution of TAGzT.

First-Principles Study of Structural and Vibrational Properties of α-SiO2 under Pressure

2015 ◽  
Vol 775 ◽  
pp. 191-196
Author(s):  
Xiao Wei Lei ◽  
Yong Song ◽  
Kuo Yang ◽  
Hui Zhao
Keyword(s):  
High Pressure ◽  
Perturbation Theory ◽  
Infrared Spectra ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Vibrational Properties ◽  
Vibrational Modes ◽  
Density Functional Perturbation Theory ◽  
Good Agreement

Using first principles approach, we present the structural, vibrational and dielectric properties of α-SiO2. The calculations have been carried out within the density functional perturbation theory and linear response formalism using the norm-concerving pseudopotentials and a plane wave basis. All the vibrational modes identified are in good agreement with experiment. The calculated infrared spectra are also in good agreement with available experimental results both for the positions and the intensities of the main peaks. We find that the modes Eu7 and A2u4 splits in two respectively at high hydrostaticpressures. Then we calculate the infrared spectra under high pressure of different orientations. The vibrational modes in different phase transitions are reported and discussed respectively.

High Pressure Properties of Superconducting Material Palladium

2013 ◽  
Vol 813 ◽  
pp. 327-331
Author(s):  
Wei Min Peng ◽  
Zhong Li Liu ◽  
Hong Zhi Fu
Keyword(s):  
High Pressure ◽  
Perturbation Theory ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Density Functional ◽  
High Pressures ◽  
Ambient Pressure ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Density Functional Perturbation Theory

The electronic and the superconducting properties of Pd were studied in the framework of density functional perturbation theory. We explored the superconducting transition temperature for bulk Pd and predicted possible superconductivity at ambient and high pressures. It is found that of Pd is 0.0356 K at ambient pressure and it decreases with pressure.

Thermodynamics of Stable and Metastable Cu-O-H Compounds

2011 ◽  
Vol 172-174 ◽  
pp. 973-978 ◽  
Author(s):  
Pavel A. Korzhavyi ◽  
Inna Soroka ◽  
Mats Boman ◽  
Börje Johansson
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Physical Properties ◽  
Density Functional ◽  
Metastable Phase ◽  
Experimental Studies ◽  
Ambient Conditions ◽  
Phonon Spectra ◽  
Density Functional Perturbation Theory ◽  
Good Agreement

We apply density functional perturbation theory together with experimental studies in order to investigate the structure and physical properties of possible stable and metastable copper(I) compounds with oxygen and hydrogen. Copper(I) hydride, CuH, is found to be a metastable phase which decomposes at ambient conditions and exhibiting a semiconducting gap in the electronic spectrum. The calculated structure and phonon spectra are found to be in good agreement with experimental data. The phonon spectra of a novel metastable phase, copper(I) hydroxide, are also determined.

Assignment of Raman-active vibrational modes of tetragonal mackinawite: Raman investigations and ab initio calculations

RSC Advances ◽  
2014 ◽  
Vol 4 (49) ◽  
pp. 25827-25834 ◽  
Author(s):  
Y. El Mendili ◽  
B. Minisini ◽  
A. Abdelouas ◽  
J.-F. Bardeau
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Density Functional ◽  
Direct Methods ◽  
Vibrational Modes ◽  
Dispersion Correction ◽  
Density Functional Perturbation Theory ◽  
Calculation Results

We report on the first assignment of the Raman-active vibrational modes of mackinawite using Density Functional Perturbation Theory and direct methods with BLYP + dispersion correction. Based on experimental data and calculation results, the Raman bands were assigned as 236 cm−1 (B1g), 256 cm−1 (Eg), 376 cm−1 (A1g) and 395 cm−1 (Eg).

scholarly journals Mechanical properties of zirconium alloys and zirconium hydrides predicted from density functional perturbation theory

2015 ◽  
Vol 44 (43) ◽  
pp. 18769-18779 ◽  
Author(s):  
Philippe F. Weck ◽  
Eunja Kim ◽  
Veena Tikare ◽  
John A. Mitchell
Keyword(s):  
Mechanical Properties ◽  
Perturbation Theory ◽  
Elastic Properties ◽  
Density Functional ◽  
Mechanical Stability ◽  
Zirconium Alloys ◽  
Density Functional Perturbation Theory ◽  
Zirconium Hydrides

The elastic properties and mechanical stability of zirconium alloys and zirconium hydrides have been investigated within the framework of density functional perturbation theory. Results show that the lowest-energy Pn3̄m δ-ZrH1.5 phase is not mechanically stable.

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