High-pressure Raman spectroscopic studies of FeS2 pyrite

2004 ◽  
Vol 68 (3) ◽  
pp. 433-441 ◽  
Author(s):  
A. K. Kleppe ◽  
A. P. Jephcoat
Keyword(s):  
Structural Phase ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
Raman Resonance ◽  
X Ray ◽  
Resonance Effects ◽  
Raman Spectroscopic ◽  
Main Effect ◽  
Raman Modes ◽  
Diamond Anvil

AbstractWe report micro-Raman spectroscopic studies of FeS2 pyrite in the diamond-anvil cell under hydrostatic and non-hydrostatic conditions to 55 GPa at room temperature. Four out of five Ramanactive modes are resolved with helium as a pressure-transmitting medium to highest pressures. The fifth mode, Tg(2) [377 cm-1], is weak and unresolved lying ∼2 cm-1 from the intense Ag mode [379 cm-1] at 1 bar. We observe an increase in the separation of the Eg [344 cm-1] and Tg(1) [350 cm-1] modes under compression. All observed frequencies increase continuously with increasing pressure showing no evidence for a structural phase transition in accord with both X-ray diffraction and shock-wave studies. The Ag and Tg(1) modes gain significantly in intensity relative to the Eg mode with increasing pressure probably resulting from Raman resonance effects. The Tg(3) mode [430 cm-1] broadens unusually compared to the other pyrite modes with pressure. The Raman data are consistent with a contraction of the S-S and Fe-S bonds under pressure. The main effect of non-hydrostatic conditions on the Raman modes is a strong pressure-induced broadening; the pressure-dependence of the frequencies and relative intensities are not affected within the error of the measurements.

scholarly journals Structural phase transition of ternary dielectric SmGdO3: Evidence from angle dispersive x-ray diffraction and Raman spectroscopic studies

2015 ◽  
Vol 117 (9) ◽  
pp. 094101 ◽  
Author(s):  
Yogesh Sharma ◽  
Satyaprakash Sahoo ◽  
A. K. Mishra ◽  
Pankaj Misra ◽  
Shojan P. Pavunny ◽  
...  
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic

scholarly journals X-ray diffraction and Raman spectroscopic studies of Zn-substituted carrboydite-like compounds

2006 ◽  
Vol 100 (1) ◽  
pp. 174-186 ◽  
Author(s):  
Yu-Hsiang Lin ◽  
Moses O. Adebajo ◽  
J. Theo Kloprogge ◽  
Wayde N. Martens ◽  
Ray L. Frost
Keyword(s):  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic

Effect of pressure on phase transitions in K1−xNaxMnF3(x = 0.04)

1999 ◽  
Vol 32 (2) ◽  
pp. 174-177 ◽  
Author(s):  
S. Åsbrink ◽  
A. Waśkowska ◽  
H. G. Krane ◽  
L. Gerward ◽  
J. Staun Olsen
Keyword(s):  
Phase Transition ◽  
Parent Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effect Of Pressure ◽  
Cell Dimensions ◽  
Main Effect ◽  
Diamond Anvil ◽  
Na Ions ◽  
Unit Cell Dimensions

The pressure-induced phase transition sequence in the title compound, potassium sodium fluoromanganate, has been investigated by single-crystal X-ray diffraction using synchrotron radiation and a diamond anvil pressure cell. Na^+ ions at 4% of the K^+ sites shift the ferrodistortive phase transition to the lower pressure P_{c1} of 2.75 (5) GPa compared to 3.12 GPa in the parent compound KMnF3. The transition is illustrated by the critical behaviour of the unit-cell dimensions, the pressure-dependent evolution of the MnF_6 ^- octahedral rotation and related macroscopic spontaneous strain. As far as precision of the present experiment allows, the observations show that the 4% of Na^+ admixture at the K^+ sites does not substantially change the nature of the transition at P_{c1}. The main effect of pressure is to stabilize the tetragonal phase II. The expected further evolution of the MnF_6 ^- octahedral tiltings, leading to the orthorhombic and monoclinic phases, has not been observed up to 8.33 GPa.

Synthesis of Zn1–xMgxO and its structural characterization

2001 ◽  
Vol 16 (4) ◽  
pp. 903-906 ◽  
Author(s):  
M. S. Tomar ◽  
R. Melgarejo ◽  
P. S. Dobal ◽  
R. S. Katiyar
Keyword(s):  
Crystal Structure ◽  
Spin Coating ◽  
Optoelectronic Devices ◽  
Spectroscopic Studies ◽  
Structural Behavior ◽  
Material System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Mg Substitution

Zn1–xMgxO is an important material for optoelectronic devices. We synthesized this material using a solution-based route. We investigated in detail the structural behavior of this material system using x-ray diffraction and Raman spectroscopy. Mg substitution up to x ≈ 0.10 does not change the crystal structure, as revealed by x-ray diffraction and Raman spectroscopic studies. This synthesis route is also suitable to prepare thin films by spin coating with the possibility of p and n doping.

Structural stability of WS2 under high pressure

2014 ◽  
Vol 28 (25) ◽  
pp. 1450168 ◽  
Author(s):  
Nirup Bandaru ◽  
Ravhi S. Kumar ◽  
Jason Baker ◽  
Oliver Tschauner ◽  
Thomas Hartmann ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Structural Changes ◽  
High Pressures ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diamond Anvil ◽  
Heating Up

Structural behavior of bulk WS 2 under high pressure was investigated using synchrotron X-ray diffraction and diamond anvil cell up to 52 GPa along with high temperature X-ray diffraction and high pressure Raman spectroscopy analysis. The high pressure results obtained from X-ray diffraction and Raman analysis did not show any pressure induced structural phase transformations up to 52 GPa. The high temperature results show that the WS 2 crystal structure is stable upon heating up to 600°C. Furthermore, the powder X-ray diffraction obtained on shock subjected WS 2 to high pressures up to 10 GPa also did not reveal any structural changes. Our results suggest that even though WS 2 is less compressible than the isostructural MoS 2, its crystal structure is stable under static and dynamic compressions up to the experimental limit.

In Situ Raman Spectroscopic Studies of Liquid Carbon Tetrachloride (CCl4) Under Static and Laser-Driven Shock Compression

2019 ◽  
Vol 73 (12) ◽  
pp. 1420-1427
Author(s):  
Usha Rao ◽  
Shivanand Chaurasia ◽  
C. D. Sijoy ◽  
Vinayak Mishra ◽  
M. N. Deo
Keyword(s):  
Carbon Tetrachloride ◽  
Shock Compression ◽  
Spectroscopic Studies ◽  
Raman Signal ◽  
Time Resolved ◽  
Raman Spectroscopic ◽  
Bending Mode ◽  
Raman Modes ◽  
Diamond Anvil ◽  
The One

High pressure (up to ∼2.2 GPa) Raman scattering studies were performed in carbon tetrachloride (CCl4) under static and dynamic compressions using diamond anvil cell (DAC) and laser-driven shock methods, respectively, and their results are compared. The laser-driven shock experiments were conducted in a glass-confined target geometry. The symmetric stretching mode ν1, symmetric bending mode ν2, and asymmetric bending mode ν4 blueshifts with pressure. Mode Gruneisen parameters were obtained for the above Raman modes. Time-resolved Raman spectroscopic (TRRS) studies were performed under laser-driven shock compression at different delay times. Shock velocity deduced from the intensity ratios of Raman signal scattered from unshocked and shocked regions of symmetric stretching mode is in agreement with the one obtained from one-dimensional hydrodynamic simulations.

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