scholarly journals Comprehensive Raman study of orthorhombic κ/ε-Ga2O3 and the impact of rotational domains

2021 ◽  
Author(s):  
Benjamin M. Janzen ◽  
Piero Mazzolini ◽  
Roland Gillen ◽  
Vivien F. S. Peltason ◽  
Linus P. Grote ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Perturbation Theory ◽  
Gallium Oxide ◽  
Density Functional ◽  
Phonon Modes ◽  
Micro Raman Spectroscopy ◽  
Density Functional Perturbation Theory ◽  
Raman Study ◽  
The Impact ◽  
Raman Active Phonon

The Raman-active phonon modes of orthorhombic gallium oxide (κ/ε-Ga2O3) are investigated by combination of polarized micro-Raman spectroscopy and density functional perturbation theory (DFPT) calculations.

Pressure dependence of the lattice dynamics of diaspore, α-AlO(OH), from Raman spectroscopy and density functional perturbation theory

2011 ◽  
Vol 38 (9) ◽  
pp. 693-700 ◽  
Author(s):  
Roberto E. San Juan-Farfán ◽  
Lkhamsuren Bayarjargal ◽  
Björn Winkler ◽  
Eiken Haussühl ◽  
Miguel Avalos-Borja ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Perturbation Theory ◽  
Pressure Dependence ◽  
Lattice Dynamics ◽  
Density Functional ◽  
Density Functional Perturbation Theory

scholarly journals Infrared and Raman spectroscopy of α-ZrW2 O8 : A comprehensive density functional perturbation theory and experimental study

2018 ◽  
Vol 49 (8) ◽  
pp. 1373-1384 ◽  
Author(s):  
Philippe F. Weck ◽  
Margaret E. Gordon ◽  
Jeffery A. Greathouse ◽  
Charles R. Bryan ◽  
Stephen P. Meserole ◽  
...  
Keyword(s):  
Experimental Study ◽  
Raman Spectroscopy ◽  
Perturbation Theory ◽  
Density Functional ◽  
Density Functional Perturbation Theory ◽  
Infrared And Raman Spectroscopy

A theoretical study of the structural and electronic properties of poly(9-vinylcarbazole) interacting with small-diameter single-walled carbon nanotubes

2020 ◽  
Vol 09 (02) ◽  
pp. 2050009
Author(s):  
V. W. Elloh ◽  
V. A. Apalangya ◽  
K. Kan-Dapaah ◽  
G. Gebreyesus ◽  
Abhishek K. Mishra ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Charge Transfer ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Small Diameter ◽  
Time Dependent ◽  
Phonon Modes ◽  
Single Walled Carbon ◽  
Density Functional Perturbation Theory ◽  
Dependent Density

Density functional perturbation theory (DFPT) and time-dependent density functional perturbation theory (TDDFPT) calculations were employed to study the molecular and electronic structures, linear and nonlinear optical properties, optical phonon modes and vibrational properties of the interaction of poly(9-vinylcarbazole) (PVK)–small-diameter single-walled carbon nanotube (SWCNT) composites. Our calculations show that the chemical connection between PVK and SWCNTs is only through the relatively weak [Formula: see text]–[Formula: see text] and [Formula: see text]–H bonds. PVK and SWCNTs have different electron accepting abilities and we believe this is the major factor responsible for the charge transfer processes we observe in the calculations. We notice an increase in polarizability value from 152 a.u. (PVK) to 517 a.u. (PVK–SWCNTs), making the PVK–SWCNT composite an ideal model for applications such as mechanical and optoelectronics. Also, the result of our calculations under the time-dependent density functional perturbation theory hinges on the idea that the large value of the polarizability calculated for our composite model is an attribute which can be inferred to processes of charge transfer. Our finding corroborates the fact that non-covalent functionalization is one of the effective chemical methods by which the nonlinear optical response properties of PVK–SWCNT composite may be enhanced.

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.

Phonon dispersion and zero-point renormalization of LiNbO3from density-functional perturbation theory

2015 ◽  
Vol 27 (38) ◽  
pp. 385402 ◽  
Author(s):  
Michael Friedrich ◽  
Arthur Riefer ◽  
Simone Sanna ◽  
W G Schmidt ◽  
Arno Schindlmayr
Keyword(s):  
Perturbation Theory ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Zero Point ◽  
Density Functional Perturbation Theory

scholarly journals Computational Modelling of Structural, Electronic, Optical and Vibrational Properties of PVK/C60 Nanoheterostructure Interfaces

2020 ◽  
Vol 11 (3) ◽  
pp. 10864-10884
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Computational Modelling ◽  
Phonon Modes ◽  
Functional Studies ◽  
Density Functional Perturbation Theory ◽  
Structural Differences ◽  
Dynamical Lattice ◽  
Quantum Espresso ◽  
Stacking Patterns

In this work, we present first-principles density functional studies of the dynamical properties of three nanoheterostructure interfaces of poly(9-vinylcarbazole)/fullerene (PVK/C60): PVK/C60(α), PVK/C60(β), and PVK/C60(γ). Linear response within density functional perturbation theory (DFPT), as implemented in the Quantum Espresso code, has been employed to explore the nature of permittivity, Born effective charges, polarizabilities, and vibrational frequency modes. The vibrational frequencies for the three nanoheterostructure interfaces were computed and their modes assigned. The phonon modes were also classified, and we showed that some important frequency modes are associated with C-C, CH2, and C−N stretching modes, among others. In addition, computed values of polarizability and permittivity for the nanoheterostructures were seen to have comparable values to that of literature for conjugated polymers. Conspicuous differing characteristics were noticed in the computed infrared and Raman absorption spectra for the three nanoheterostructures, which was due to the structural differences arising from their different stacking patterns. It is noted that the presence of the nitrogen atom plays a significant role in determining their dynamical lattice properties. The permittivity and polarizability tensors of PVK/C60(α), PVK/C60(β), and PVK/C60(γ) nanoheterostructures were found to be strongly anisotropic.

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