Study of Optical Vibrations Modes of Mineral Graphite by Micro Raman Spectroscopy

2012 ◽  
Vol 1481 ◽  
pp. 37-43
Author(s):  
R. A. Silva-Molina ◽  
R. Gámez-Corrales ◽  
J. M. Hernández-Cazares ◽  
I. G. Espinoza-Maldonado
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Second Order ◽  
Defect Band ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Combination Scattering ◽  
Degree Of Graphitization

ABSTRACTWe present experimental and theoretical Raman spectra of natural graphite mineral of Sonora, Mexico. In this work, we take the advantage of the utility of the RAMAN spectroscopy as a technique to determine the crystallinity and structure of graphite mineral. The RAMAN spectroscopy provides information that can be used to determine the degree of graphitization, which in turn can be used to know the metamorphic degree of the host rock. The resulting RAMAN spectra of graphite were divided in first and second order regions, in the first region (1100-1800cm-1) the E2gvibration mode with D6hcrystal symmetry occurs at 1580cm-1(G band) that indicates poorly organized graphite, additional bands appears in the first order region at 1350 cm-1(D band) called the defect band, and another at 1620 cm-1(D* band). The second-order region (2200-3400cm-1) shows several bands at ~2400 ~2700 ~2900 ~3300cm-1, all of them attributed to electron-phonon interactions or combination scattering. The density functional theory calculations were applied to determine the vibrational properties and the stacking layers of graphite.

scholarly journals Synthesis, Mass Spectroscopy Detection, and Density Functional Theory Investigations of the Gd Endohedral Complexes of C82 Fullerenols

Computation ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 58
Author(s):  
Anastasia A. Shakirova ◽  
Felix N. Tomilin ◽  
Vladimir A. Pomogaev ◽  
Natalia G. Vnukova ◽  
Grigory N. Churilov ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Mass Spectrometry Analysis ◽  
Structure And Properties ◽  
Functional Theory ◽  
Endohedral Complexes ◽  
Spectrometry Analysis ◽  
The Density Functional Theory ◽  
Atomic And Electronic Structure

Gd endohedral complexes of C82 fullerenols were synthesized and mass spectrometry analysis of their composition was carried out. It was established that the synthesis yields a series of fullerenols Gd@C82Ox(OH)y (x = 0, 3; y = 8, 16, 24, 36, 44). The atomic and electronic structure and properties of the synthesized fullerenols were investigated using the density functional theory calculations. It was shown that the presence of endohedral gadolinium increases the reactivity of fullerenols. It is proposed that the high-spin endohedral fullerenols are promising candidates for application in magnetic resonance imaging.

Theoretical study of SnS2 encapsulated in Graphene as a promising anode material for K−ion batteries

2021 ◽  
Author(s):  
Xuxin Kang ◽  
Wei Xu ◽  
Xiangmei Duan
Keyword(s):  
Anode Material ◽  
Density Functional ◽  
Open Circuit Voltage ◽  
Electronic Conductivity ◽  
Density Functional Theory Calculations ◽  
Rechargeable Batteries ◽  
Open Circuit ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Low K

Abstract Rechargeable batteries with superior electronic conductivity, large capacity, low diffusion barriers and moderate open circuit voltage have attracted amount attention. Due to abundant resources and safety, as well as the high voltage and energy density, potassium ion batteries (KIBs) could be an ideal alternative to next−generation of rechargeable batteries. Based on the density functional theory calculations, we find that the SnS2 monolayer expands greatly during the potassiumization, which limits its practical application. The construction of graphene/SnS2/graphene (G/SnS2/G) heterojunction effectively prevents SnS2 sheet from deformation, and enhances the electronic conductivity. Moreover, the G/SnS2/G has not only a high theoretical special capacity of 680 mAh/g, but an ultra−low K diffusion barrier (0.08 eV) and an average open circuit voltage (0.22 V). Our results predict that the G/SnS2/G heterostructure could be used as a promising anode material for KIBs.

scholarly journals Investigation of the cis–trans structures and isomerization of oligoprolines by using Raman spectroscopy and density functional theory calculations: solute–solvent interactions and effects of terminal positively charged amino acid residues

RSC Advances ◽  
2020 ◽  
Vol 10 (57) ◽  
pp. 34493-34500
Author(s):  
Mei-Chun Huang ◽  
Wei-Hao Chen ◽  
Chen-Wei Huang ◽  
Kuei-Yen Huang ◽  
Jia-Cherng Horng ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Raman Spectroscopy ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Density Functional Theory Calculations ◽  
State Density ◽  
Amino Acid Residues ◽  
Functional Theory ◽  
Solvent Interactions ◽  
Positively Charged

The low-wavenumber Raman spectra in combination with theoretical calculations via solid-state density functional theory (DFT)-D3 are displayed. The vibrational structures and interaction with solvent of poly-l-proline and the oligoproline P12 series are identified.

Density functional study of the phase stability and Raman spectra of Yb2O3, Yb2SiO5 and Yb2Si2O7 under pressure

2018 ◽  
Vol 20 (24) ◽  
pp. 16518-16527 ◽  
Author(s):  
Takafumi Ogawa ◽  
Noriko Otani ◽  
Taishi Yokoi ◽  
Craig A. J. Fisher ◽  
Akihide Kuwabara ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrostatic Pressure ◽  
Raman Spectra ◽  
Phase Stability ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Study ◽  
Functional Theory ◽  
Density Functional Study

The phase stability and Raman spectra of Yb2O3, Yb2SiO5 and Yb2Si2O7 under hydrostatic pressure are investigated using density functional theory calculations.

scholarly journals Large Uniaxial Magnetic Anisotropy of Hexagonal Fe-Hf-Sb Alloys

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 430
Author(s):  
Lukas Kyvala ◽  
Maxim Tchaplianka ◽  
Alexander Shick ◽  
Sergii Khmelevskyi ◽  
Dominik Legut
Keyword(s):  
Density Functional Theory ◽  
Magnetic Anisotropy ◽  
Permanent Magnet ◽  
Chemical Control ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Magnetization Direction ◽  
Functional Theory ◽  
Uniaxial Magnetic Anisotropy ◽  
The Density Functional Theory

We theoretically investigate the electronic and magnetic structure of Fe 2 Hf. The density functional theory calculations are shown to produce the negative, easy-plane, magnetic anisotropy in the hexagonal Fe 2 Hf. Antimony substitution suppresses the planar magnetization direction and favors the uniaxial magnetic anisotropy, in agreement with experimental observations. Our study suggests the possibility of the chemical control of the magnetic anisotropy in Fe 2 Hf by Sb substitution, and illustrates the potential of (Fe,Sb) 2 + x Hf 1 − x Laves phase alloys for the permanent magnet applications.

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