Raman Spectra in Molecular Solids: III.—Determination of the Phase Diagram of Solid P-Dichlorobenzene by High Pressure Raman Spectroscopy: Spoliation of the α-Phase

1974 ◽  
Vol 27 (3-4) ◽  
pp. 305-314 ◽  
Author(s):  
P. Figuiere ◽  
H. Szwarc
Keyword(s):  
Phase Diagram ◽  
Raman Spectroscopy ◽  
High Pressure ◽  
Raman Spectra ◽  
Molecular Solids ◽  
Α Phase

High-pressure ultrasonic determination of the phase diagram of antiferromagnetic Cr-0.3 at.% Ru alloy single-crystal

1993 ◽  
Vol 172 (5) ◽  
pp. 387-390 ◽  
Author(s):  
H.A.A. Sidek ◽  
M. Cankurtaran ◽  
G.A. Saunders ◽  
P.J. Ford ◽  
H.L. Alberts
Keyword(s):  
Phase Diagram ◽  
High Pressure ◽  
Single Crystal ◽  
Alloy Single Crystal ◽  
Ultrasonic Determination

scholarly journals Depolarization Ratios of Methane Raman Bands as a Function of Pressure

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1951
Author(s):  
Dmitry Petrov
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Natural Gas ◽  
Raman Spectra ◽  
Pressure Dependence ◽  
Pressure Range ◽  
Gas Composition ◽  
Depolarization Ratio ◽  
Depolarization Ratios

In this work, we measured the intensities of Q-branches of the ν1, ν2 and ν3 bands in the polarized and depolarized methane Raman spectra in the pressure range of 1–60 atm. It was established that the pressure dependence of depolarization ratios of the ν2 and ν3 bands are negligible. In turn, the depolarization ratio of the ν1 band increases with increasing pressure and reaches approximately 0.0045 at 60 atm. These data are more precise than previously published ones because ν1 band intensities were determined taking into account the contribution of overlapping lines of ν3 band. The presented data will be useful in calculating the methane polarizabilities at high pressure, as well as in calculating methane Raman spectra for measuring the natural gas composition using Raman spectroscopy.

Determination of the Resolution of a Multichannel Raman Spectrometer Using Fourier Transform Raman Spectra

2003 ◽  
Vol 57 (2) ◽  
pp. 190-196 ◽  
Author(s):  
Bryan T. Bowie ◽  
Peter R. Griffiths
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Raman Spectra ◽  
Shape Function ◽  
Raman Spectrometer ◽  
Fourier Transform Raman ◽  
Nominal Resolution ◽  
Line Shape Function ◽  
Ft Raman

The resolution of a grating polychromator for Raman spectroscopy has been simulated by measuring spectra on a Fourier transform (FT) Raman spectrometer and selecting the FT of the apodization function so that the instrument line shape function mimics the triangular spectral slit function of the polychromator. To this end, FT-Raman spectra measured with a nominal resolution of 0.5 cm−1 were modified through the application of sinc2 apodization functions of various widths to simulate spectra measured on a polychromator at lower resolution. The success of this approach was validated using the 1085 cm−1 band of calcite. When the modified FT-Raman spectra were compared with spectra measured on a grating polychromator equipped with slits of widths 100 and 150 μm, the resolution of the polychromator was estimated to be 6.3 and 7.8 cm−1, respectively. This conclusion was verified experimentally by measuring the separation of two bands in the Raman spectrum of BaSO4 at ∼460 cm−1

Nanoindentation-Induced Phase Transformation in Silicon Thin Films

2013 ◽  
Vol 586 ◽  
pp. 112-115 ◽  
Author(s):  
Radim Ctvrtlik ◽  
Jan Tomastik ◽  
Vaclav Ranc
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
High Pressure ◽  
Phase Transformation ◽  
Raman Spectra ◽  
Structural Changes ◽  
Berkovich Indenter ◽  
Silicon Thin Films ◽  
Free Silicon ◽  
Amorphous Si

Nanoindentation-induced phase transformation of amorphous, annealed amorphous and microcrystalline hydrogen-free silicon thin films were studied. Series of nanoindentation experiments were performed with a sharp Berkovich indenter at various unloading rates. The structural changes in indentation deformed regions were examined using Raman spectroscopy. Analyses of indentation curves and Raman spectra suggest that high pressure phases appear more easily in annealed amorphous Si thin films than in microcrystalline ones.

scholarly journals Relaxor ferroelectrics materials under high pressure

2014 ◽  
Vol 70 (a1) ◽  
pp. C979-C979
Author(s):  
Arthur Haozhe Liu ◽  
Lisa Luhong Wang ◽  
Lingping Kong
Keyword(s):  
Phase Diagram ◽  
Raman Spectroscopy ◽  
High Pressure ◽  
High Temperature ◽  
Relaxor Ferroelectrics ◽  
Ferroelectric Materials ◽  
Structure Evolution ◽  
Cubic Phase ◽  
Temperature Phase ◽  
Temperature Conditions

The rich phase diagrams from both relaxor and normal ferroelectrics under high pressure, stimulate us to study the pressure effect on the relaxor-PbTiO3 (PT) systems, to check whether the high pressure cubic structure will turn to low symmetry structure upon strong compression is the common behaviors for relaxor ferroelectrics materials. Furthermore, a complete phase diagram study of pressure-temperature effect on structure will allow us to explore the limitation on applications of relaxor-PT material devices under harsh environment involving in high pressure and high temperature conditions. Structure evolution and phase transition of several solid solution ferroelectrics, such as Pb(YbNb)O3-PT (PYN-PT), have been studied using in situ synchrotron X-ray diffraction (XRD) and Raman spectroscopy techniques under high pressure and high temperature conditions. XRD results show pressure induced phase transitions to a cubic phase, while the persistence of Raman spectroscopy in the full pressure range indicates its local distortion. A pressure-temperature phase diagram is further constructed to determine the stability region of the ferroelectric phase. The results provide useful guidance for the applications of this kind of high Curie temperature ferroelectric crystal under extreme conditions, and extra clue to synthesis of ferroelectric materials with tailored properties.

Raman and FTIR Spectroscopy of Synthetic Amphiboles: I. The OH Librational Bands and the Determination of the OH-F Content of Richterites via Raman Spectroscopy

2020 ◽  
Author(s):  
Giancarlo Della Ventura ◽  
Frank C. Hawthorne ◽  
Boriana Mihailova ◽  
Armida Sodo
Keyword(s):  
Raman Spectroscopy ◽  
Ftir Spectroscopy ◽  
Raman Spectra ◽  
Energy Region ◽  
Low Energy ◽  
Reliable Estimation ◽  
A Site ◽  
Combination Bands ◽  
Two Peaks

Abstract Unpolarized FTIR and Raman spectra were collected in the regions 4000–4600 cm–1 (NIR) and 100–4000 cm–1 from previously synthesized and characterized amphiboles in the systems richterite–fluoro-richterite, potassic-richterite–potassic-fluoro-richterite, rubidium-richterite–rubidium-fluoro-richterite, and potassic-richterite–deuterated potassic-richterite. The NIR spectra of Na-, K-, and Rb-richterites have peaks at 4325, 4210 cm–1, and 3735–3730 cm–1. All three peaks decrease in intensity with increasing F content, indicating that the higher-energy peaks are combination bands involving the principal OH-stretch at 3735–3730 cm–1 and two OH-libration modes, the frequencies of which can be calculated from the relation ωcombination ≈ ωOH + ωlibration; these are 590 and 475 cm–1, respectively. The FTIR spectra of the richterite–fluoro-richterite and potassic-richterite–potassic-fluoro-richterite series show decreasing intensity and eventual disappearance of the band at ∼600 cm–1 with increasing F in accord with the assignment of this band as due to OH-libration. Raman spectra of the potassic-richterite–deuterated potassic-richterite amphiboles in the low-energy region show the disappearance of two peaks at 585 and 473 cm–1 that we have assigned to OH-libration modes. Collectively, these spectroscopic results indicate that there are two OH-libration modes at ∼590 and ∼475 cm–1 in these synthetic richterites and, by implication, in all monoclinic OH-bearing amphiboles with filled A sites. Similarly to FTIR, the relative intensities of the stretching modes associated with OH-A-OH and OH-A-F local configurations in the Raman spectra provide a reliable estimation of the F content in these A site-filled amphiboles.

Raman Spectroscopy Allows for the Determination of Elephant Ivory Age

2020 ◽  
Vol 74 (8) ◽  
pp. 940-947
Author(s):  
Anna Sharikova ◽  
Lubna Peerzada ◽  
Kai Pisila ◽  
Tine Chean Khoo ◽  
Alexander Cherkinsky ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Raman Signal ◽  
Nondestructive Technique ◽  
Data Set ◽  
Portable System ◽  
Vibrational Bands ◽  
Elephant Ivory ◽  
Value Decomposition

Determination of the age of ivory is important for controlling illegal trafficking and the proper identification of ivory artifacts. Radiocarbon dating is the standard method of determining the age of ivories; however, it requires the destruction of a fragment of the sample. Raman spectroscopy is a nondestructive technique, and therefore can be used on artwork. Moreover, Raman measurements can be done using a portable system, and the data analysis can be performed on the spot once the groundwork is done. Ivories contain two primary components: collagen and bioapatite. Raman spectrum of ivory material is mainly a sum of the vibrational bands of these components. As collagen deteriorates with time, its Raman signal decreases; therefore, the ratio of collagen to bioapatite peaks is smaller in the older samples compared to the younger ones, providing a basis for sample dating. We have compared the results of Raman and radiocarbon measurements applied to a set of elephant ivory fragments and have successfully calibrated the Raman data set using radiocarbon measurements. We found that the Raman collagen to bioapatite peak ratios of the samples can be used as a metric to determine their age, providing a nondestructive technique to assess the age of ivory samples. We have also used singular value decomposition (SVD) to analyze the whole Raman spectra. We have observed clear separation between samples of different ages in the SVD component space. The samples also tended to align along the timeline diagonal in the correct order. The changes in multiple collagen and bioapatite peaks contribute to the differences in Raman spectra of ivory samples of different age.

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