On the use of diamond as a pressure calibrant for near-infrared FT–Raman microspectroscopy at high pressures

1995 ◽  
Vol 73 (7) ◽  
pp. 1019-1022 ◽  
Author(s):  
Ross D. Markwell ◽  
Ian S. Butler
Keyword(s):  
Near Infrared ◽  
Phonon Mode ◽  
High Pressures ◽  
Ambient Pressure ◽  
Raman Microspectroscopy ◽  
Near Ir ◽  
Ft Raman Spectroscopy ◽  
Diamond Anvil ◽  
Ft Raman

The pressure-induced shift of the Raman-active t2g phonon mode of the diamond windows in a commercial diamond-anvil cell, located at l332.5 cm−1 at ambient pressure, can be used as an in situ calibrant for near-IR FT–Raman microspectroscopy at high pressures. The measured pressures are considered to be accurate to within ±2 kbar throughout the 4–45 kbar range for which the associated pressure (P, kbar) vs. wavenumber (v, cm−1) relationship is P = 6.66v − 1335.9. Keywords: FT–Raman spectroscopy, diamond, high pressures.

Biological applications of near- IR fourier-transform Raman microspectroscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1530-1531
Author(s):  
Yukihiro Ozaki
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Photosynthetic Bacteria ◽  
Near Infrared ◽  
Raman Microspectroscopy ◽  
Excitation Wavelength ◽  
Near Ir ◽  
Ft Raman Spectroscopy ◽  
Sample Position ◽  
Ft Raman

Recently-developed near-infrared Fourier transform (FT)-Raman spectroscopy has received keen interest of researchers in bio-Raman field because near-infrared excitation can avoid mostly fluorescence and photodecomposition, which have been two major drawbacks of Raman spectroscopy in its biological and medical applications. Introduction of FT-Raman microspectroscopy makes near-infrared FT-Raman spectroscopy more useful for studying biomedical materials. The purpose of the present paper is to demonstrate the potential of near-infrared FT-Raman microspectroscopy in nondestructive structural analysis of biological systems. Photosynthetic bacteria is taken up here as an example.The FT-Raman spectra of the photosynthetic bacteria were measured with a JEOL JRS-FT6500N FT-Raman spectrometer equipped with an optical microscopy. Excitation wavelength at 1064-nm was provided by a CW Nd:YAG laser (CVI YAGMAX c-92), and the laser power at the sample position was typically 150 mW. All the data were collected at a spectral resolution of 8 cm-1 and spatial resolution of 8 μm.

On-Line Monitoring of Airborne Chemistry in Levitated Nanodroplets:  In Situ Synthesis and Application of SERS-Active Ag−Sols for Trace Analysis by FT-Raman Spectroscopy

2003 ◽  
Vol 75 (9) ◽  
pp. 2166-2171 ◽  
Author(s):  
Nicolae Leopold ◽  
Michael Haberkorn ◽  
Thomas Laurell ◽  
Johan Nilsson ◽  
Josefa R. Baena ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Trace Analysis ◽  
In Situ Synthesis ◽  
Ft Raman Spectroscopy ◽  
On Line ◽  
Ft Raman

Application of FT-Raman spectroscopy to the study of selected organometallic complexes and proteins

1990 ◽  
Vol 68 (7) ◽  
pp. 1196-1200 ◽  
Author(s):  
Steven M. Barnett ◽  
François Dicaire ◽  
Ashraf A. Ismail
Keyword(s):  
Raman Spectroscopy ◽  
Near Infrared ◽  
Metal Carbonyl ◽  
Protein A ◽  
Organometallic Complexes ◽  
Laser Source ◽  
Chromium Tricarbonyl ◽  
Ft Raman Spectroscopy ◽  
Arene Chromium Tricarbonyl ◽  
Ft Raman

The study of colored organometallic complexes by dispersive Raman spectroscopy has been limited due to fluorescence or photodecomposition caused by the visible laser used as the excitation source. As a solution to this problem, FT-Raman spectroscopy with a near-infrared laser source has been useful in lowering fluorescence or photolysis in these samples. To investigate the utility of this technique, we have obtained and assigned the FT-Raman spectra of a series of arene chromium tricarbonyl complexes and of cyclopentadienyl manganese tricarbonyl. Some bands previously unobserved by dispersive Raman spectroscopy were seen, including a band assigned to a 13CO satellite in the spectrum of methylbenzoate chromium tricarbonyl. In addition, FT-Raman data for bovine serum albumin (BSA) and Protein-A are presented. Keywords: FT-Raman spectroscopy, metal carbonyl, proteins, organometallics, near infrared.

Potential of Near-Infrared Fourier Transform Raman Spectroscopy in Food Analysis

1992 ◽  
Vol 46 (10) ◽  
pp. 1503-1507 ◽  
Author(s):  
Y. Ozaki ◽  
R. Cho ◽  
K. Ikegaya ◽  
S. Muraishi ◽  
K. Kawauchi
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Fatty Acid ◽  
Raman Spectra ◽  
Food Analysis ◽  
Near Infrared ◽  
Egg White ◽  
Ft Raman Spectroscopy ◽  
Ft Raman

The 1064-nm excited Fourier transform (FT) Raman spectra have been measured in situ for various foods in order to investigate the potential of near-infrared (NIR) FT-Raman spectroscopy in food analysis. It is demonstrated here that NIR FT-Raman spectroscopy is a very powerful technique for (1) detecting selectively the trace components in foodstuffs, (2) estimating the degree of unsaturation of fatty acids included in foods, (3) investigating the structure of food components, and (4) monitoring changes in the quality of foods. Carotenoids included in foods give two intense bands near 1530 and 1160 cm−1 via the pre-resonance Raman effect in the NIR FT-Raman spectra, and therefore, the NIR FT-Raman technique can be employed to detect them nondestructively. Foods consisting largely of lipids such as oils, tallow, and butter show bands near 1658 and 1443 cm−1 due to C=C stretching modes of cis unsaturated fatty acid parts and CH2 scissoring modes of saturated fatty acid parts, respectively. It has been found that there is a linear correlation for various kinds of lipid-containing foods between the iodine value (number) and the intensity ratio of two bands at 1658 and 1443 cm−1 ( I1658/ I1443), indicating that the ratio can be used as a practical indicator for estimating the unsaturation level of a wide range of lipid-containing foods. A comparison of the Raman spectra of raw and boiled egg white shows that the amide I band shifts from 1666 to 1677 cm−1 and the intensity of the amide III band at 1275 cm−1 decreases upon boiling. These observations indicate that most α-helix structure changes into unordered structure in the proteins constituting egg white upon boiling. The NIR FT-Raman spectrum of old-leaf (about one year old) Japanese tea has been compared with that of its new leaf. The intensity ratio of two bands at 1529 and 1446 cm−1 ( I1529/ I1446), assignable to carotenoid and proteins, respectively, is considerably smaller in the former than in the latter, indicating that the ratio is useful for monitoring the changes in the quality of Japanese tea.

Near-IR FT-Raman Spectroscopy of Methyl-B12and Other Cobalamins and of Imidazole and Imidazolate Methylcobinamide Derivatives in Aqueous Solution

1996 ◽  
Vol 35 (16) ◽  
pp. 4656-4662 ◽  
Author(s):  
James M. Puckett, ◽  
Mark B. Mitchell ◽  
Shun Hirota ◽  
Luigi G. Marzilli
Keyword(s):  
Aqueous Solution ◽  
Raman Spectroscopy ◽  
Near Ir ◽  
Ft Raman Spectroscopy ◽  
Ft Raman

Structure–melting relations in isomeric dibromobenzenes

2014 ◽  
Vol 70 (3) ◽  
pp. 492-497 ◽  
Author(s):  
Kamil F. Dziubek ◽  
Andrzej Katrusiak
Keyword(s):  
Melting Point ◽  
Ambient Pressure ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Diamond Anvil ◽  
Higher Temperature

1,4-Dibromobenzene melts at a considerably higher temperature than the 1,2- and 1,3-isomers. This melting-point difference is consistent with the molecular symmetry, as described by Carnelley's rule, and with the frequency of Br...Br halogen bonds. The lowest melting point of 1,3-dibromobenzene correlates with its two symmetry-independent molecules, indicating their inability to pack closely. Single crystals of 1,2- and 1,3-dibromobenzene have been grown under isochoric conditions in a diamond–anvil cell and at isobaric conditions in a glass capillary. Their structures have been determinedin situby X-ray diffraction. At 295 K 1,2-dibromobenzene crystallizes at 0.2 GPa as orthorhombic, space groupPbca,Z′ = 1, and 1,3-dibromobenzene at 0.3 GPa as orthorhombic, space groupP212121,Z′ = 2. The same crystal phases are formed at ambient pressure by freezing these liquids below 256.15 and 248.45 K, respectively. The third isomer, 1,4-dibromobenzene, is a solid at room temperature and crystallizes as monoclinic, space groupP21/a. Striking relations between the structures and melting points of the corresponding dibromobenzene and dichlorobenzene isomers have been discussed.

High-pressure transformations of NbO2F

2000 ◽  
Vol 56 (2) ◽  
pp. 189-196 ◽  
Author(s):  
Stefan Carlson ◽  
Ann-Kristin Larsson ◽  
Franziska E. Rohrer
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
High Pressures ◽  
Ambient Pressure ◽  
Close Packing ◽  
Hexagonal Close Packing ◽  
Rietveld Refinements ◽  
X Ray ◽  
Anion Coordination ◽  
Diamond Anvil

The ReO3-type structure NbO2F, niobium dioxyfluoride, has been studied at high pressures using diamond anvil cells and synchrotron X-ray radiation. High-pressure powder diffraction measurements have been performed up to 40.1 GPa. A phase transition from the cubic (Pm3¯m) ambient pressure structure to a rhombohedral (R3¯c) structure at 0.47 GPa has been observed. Rietveld refinements at 1.38, 1.96, 3.20, 6.23, 9.00 and 10.5 GPa showed that the transition involves an a − a − a − tilting of the cation–anion coordination octahedra and a change of the anion–anion arrangement to approach hexagonal close packing. Compression and distortion of the Nb(O/F)6 octahedra is also revealed by the Rietveld refinements. At 17–18 GPa, the diffraction pattern disappears and the structure becomes X-ray amorphous.

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