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Fourier transform spectroscopy

About: Fourier transform spectroscopy is a research topic. Over the lifetime, 5418 publications have been published within this topic receiving 134133 citations.


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Journal ArticleDOI
TL;DR: FTIR spectroscopy has been used to monitor and determine the degree of crystallisation in a sample of polyhydroxybutyrate-co-14%valerate (PHB–co- 14%HV), and PCA has been shown to be suitable for determining the number of dynamic spectral features and has enabled relative and objective monitoring of crystallised kinetics.
Abstract: FTIR spectroscopy has been used to monitor and determine the degree of crystallisation in a sample of polyhydroxybutyrate-co-14%valerate (PHB-co-14%HV). Time series spectra of solution-cast films of the polymer revealed spectral changes attributed to the onset of crystallisation. Curve fitting was used to obtain an absolute measure of crystallinity. Mean centred principal-component analysis (PCA) revealed that 99.9% of the spectral variance could be attributed to factor 1. The loadings plot for factor 1 contained features attributable to crystalline and amorphous phases. These features were opposite in sign, indicating that changes in the spectra with the onset of crystallisation are simultaneous and opposite in direction, i.e. as the crystalline band increases the amorphous band decreases. Cross-peaks in asynchronous 2D correlation maps indicate there are likely to be very minor components that are changing out of phase. The presence of these minor components is supported by examination of the loadings of higher factors in the PCA model. PCA has been shown to be suitable for determining the number of dynamic spectral features and has enabled relative and objective monitoring of crystallisation kinetics.

64 citations

Journal ArticleDOI
TL;DR: In this article, single crystals of the nonlinear optical material, l-arginine bis(trifluoroacetate), with dimensions of 32 × 21 × 4 mm3 were grown by the temperature-lowering method from its aqueous solution.
Abstract: Single crystals of the nonlinear optical material, l-arginine bis(trifluoroacetate), with dimensions of 32 × 21 × 4 mm3 were grown by the temperature-lowering method from its aqueous solution. The crystal structure was determined using X-ray single-crystal diffraction at 93 K. X-ray powder diffraction, Fourier transform infrared, and Raman spectroscopic investigations were used to characterize the grown crystal. Morphological analysis reveals that the crystal is a rhombohedron with the major forms of (001), (101), and (100). UV−visible−NIR absorption spectrum and second harmonic generation were investigated to explore its characteristic optical features. Thermogravimetric (TG), differential thermal analysis (DTA), derivative thermogravimetric (DTG), and differential scanning calorimetry (DSC) studies were carried out to characterize the thermal behaviors of the grown crystals. In addition, the specific heat at low temperature and thermal expansion coefficients along the principal axes were determined. I...

63 citations

Journal ArticleDOI
TL;DR: In this article, the polymorphism of m-aminobenzoic acid has been investigated and two polymorphs have been identified and characterized by X-ray powder diffraction (XRPD), Fourier transform IR (FTIR), microscopy, and...
Abstract: The polymorphism of m-aminobenzoic acid has been investigated. Two polymorphs have been identified and characterized by X-ray powder diffraction (XRPD), Fourier transform IR (FTIR), microscopy, and ...

63 citations

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate submillimetre-wave Fourier transform spectroscopy as a novel technique for biological molecule characterization and present a computational method to predict the low-frequency absorption spectra of short artificial DNA and RNA.
Abstract: We demonstrate submillimetre-wave Fourier transform spectroscopy as a novel technique for biological molecule characterization. Transmission measurements are reported at frequencies 10–25 cm−1 for single- and double-stranded RNA molecules of known base-pair sequences: homopolymers poly[A], poly[U], poly[C] and poly[G], and double-stranded homopolymers poly[A]–poly[U] and poly[C]–poly[G]. Multiple resonances are observed (i.e. in the microwave through terahertz frequency regime). We also present a computational method to predict the low-frequency absorption spectra of short artificial DNA and RNA. Theoretical conformational analysis of molecules was utilized to derive the low-frequency vibrational modes. Oscillator strengths were calculated for all the vibrational modes in order to evaluate their weight in the absorption spectrum of a molecule. Normal modes and absorption spectra of the double-stranded RNA chain poly[C]–poly[G] were calculated. The absorption spectra extracted from the experiment were directly compared with the results of computer modelling thereby, confirming the fact that observed spectral features result from electromagnetic wave interactions with the DNA and RNA macromolecules. Correlation between experimental spectrum and modelling results demonstrates the ability of normal mode analysis to reproduce RNA vibrational spectra.

63 citations

Journal ArticleDOI
09 Jan 1976-Science
TL;DR: This lab will focus on the chemical structures of certain substances, however IR spectroscopy is used for obtaining an abundance of information such as thermodynamic data, bond length and diffusion data.
Abstract: IR spectroscopy is an important relatively inexpensive and efficient analytical method for characterizing materials. In this lab we will focus on the chemical structures of certain substances, however IR spectroscopy is used for obtaining an abundance of information such as thermodynamic data, bond length and diffusion data. On the other hand IR spectroscopy is limited in the ability to obtain accurate quantitative measurements and the range of inorganic materials that are IR visible. The spectrum that is obtained from IR spectroscopy is due to the vibrational modes of the molecules. Each molecule has its own distinct quantized vibrational energy level. This is often termed its ‘fingerprint’. In FTIR, electromagnetic radiation in the infrared region is directed at the sample. When the frequency of this energy matches the frequency of the vibration of the molecules, radiation is absorbed (or transmitted). Below is an example of an IR spectrum.

63 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202334
2022117
202171
202076
2019108
201888