Source Fourier Transform infrared

Time-resolved Fourier transform infrared spectroscopy has been used surprisingly little considering the nuadter of commercial spectrometers that are currently in laboratories and the applicability of this technique to the difficult tine regime from a few is to a few hundred is. One problem with time-resolved Fourier transform spectroscopy and possibly one reason that it has not been more widely used is the stringent reproducibility requirement of the repetitive event in order to avoid artifacts in the spectra( ). When changes occur in the eiaissirr source over the course of a... 

A significant advance was the application of the Fourier transform technique to enhance the signal. The optical arrangement of a Fourier transform infrared (FUR) spectrometer is shown in Fig. 27.37 (Habib and Bockris, 1984). A beam of light from an IR source is directed to a beamsplitter, where part of the beam is transmitted to a... 

Miniaturized chemical analysis systems have been developed for most macroscopic counterparts (Dittrich et al. 2006). The availability of optical fibers, light sources, and detectors in the visible UV and near-infrared (NIR) wavelengths makes it possible to integrate spectroscopic measurements in microreactors (Lobbecke et al. 2005). Fourier transform infrared spectroscopy (FTIR) is an efficient, broadly applicable... 

A Fourier transform infrared spectroscopy spectrometer consists of an infrared source, an interference modulator (usually a scanning Michelson interferometer), a sample chamber and an infrared detector. Interference signals measured at the detector are usually amplified and then digitized. A digital computer initially records and then processes the interferogram and also allows the spectral data that results to be manipulated. Permanent records of spectral data are created using a plotter or other peripheral device. 

The most recent advance in VCD instrumentation has been its adaptation to Fourier transform infrared (FTIR) measurement (23-25). The details of this technique involve a new method of FTIR measurement termed double-modulation FTIR spectroscopy. Thus spectra of very high quality and resolution have been obtained using a standard VCD modulator and detector, a glower source, and a commercially available FTIR spectrometer system. In fact an entire FTIR-VCD spectrometer can be assembled from a few commercially available components. It is found that the major advantages of resolution, throughput, and... 

Both APPL s produce similar patterns when analyzed by Fourier Transform infrared (FTIR) spectroscopy, which are quite different from the spectrum of Indulin ATR (Figure 4). Table V sums up the major differences between these spectra. Figure 5 provides further proof that there is no contamination by yeast extract the pattern of APPL produced by S. badius using glucose as carbon source is identical to that of APPL obtained using yeast extract (same data for S. viridosporus not shown). 

Fourier transform infrared spectrometers first appeared in the 1970s. These single beam instruments, which differ from scanning spectrometers, have an interferometer of the Michelson type placed between the source and the sample, replacing the monochromator (Figs 10.9c and 10.11). 

The heart of a Fourier transform infrared spectrophotometer is the interferometer in Figure 20-26. Radiation from the source at the left strikes a beamsplitter, which transmits some light and reflects some light. For the sake of this discussion, consider a beam of monochromatic radiation. (In fact, the Fourier transform spectrophotometer uses a continuum source of infrared radiation, not a monochromatic source.) For simplicity, suppose that the beamsplitter reflects half of the light and transmits half. When light strikes the beamsplitter at point O, some is reflected to a stationary mirror at a distance OS and some is transmitted to a movable mirror at a distance OM. The rays reflected by the mirrors travel back to the beamsplitter, where half of each ray is transmitted and half is reflected. One recombined ray travels in the direction of the detector, and another heads back to the source. 

Figure 20-29 Fourier transform infrared spectrum of polystyrene film. The Fourier transform of the background interferogram gives a spectrum determined by the source intensity, beamsplitter efficiency, detector response, and absorption by traces of H20 and C02 in the atmosphere. The sample compartment is purged with dry N2 to reduce the levels of H20 and C02. The transform of the sample interferogram is a measure of all the instrumental factors, plus absorption by the sample. The transmission spectrum is obtained by dividing the sample transform by the background transform.

X-ray photoelectron spectroscopy (XPS) was used for elemental analysis of plasma-deposited polymer films. The photoelectron spectrometer (Physical Electronics, Model 548) was used with an X-ray source of Mg Ka (1253.6 eV). Fourier transform infrared (FTIR) spectra of plasma polymers deposited on the steel substrate were recorded on a Perkin-Elmer Model 1750 spectrophotometer using the attenuated total reflection (ATR) technique. The silane plasma-deposited steel sample was cut to match precisely the surface of the reflection element, which was a high refractive index KRS-5 crystal. 

Fourier transform infrared (FTIR) spectroscopy has been extensively developed over the past decade and provides a number of advantages. The main part of FTIR spectrophotometer is the Michelson interferometer. Radiation containing all IR wavelengths (e.g., 4000-400 cm 1) is emitted by source of infrared radiation (Globar) and is split into two beams. One beam is of fixed length, and the other is of variable length (movable mirror). 

It is clear that the introduction of the IR FPA detector has brought Fourier transform infrared (FTIR) microscopy with a thermal source to a new and exciting stage of development. This is illustrated in the other chapters of this volume. Our purpose in this chapter is to address how IR FPA technology could be combined with the synchrotron source to advance IR spectroscopic imaging in ways that would prove quite difficult with a conventional thermal source. To address this question, we will need to understand the detailed nature of the synchrotron IR source, the optical... 

Diem, M., Romeo, M., Matthas, C., Miljkovic, M., Miller, L. and Lasch, P. (2004) Comparison of Fourier transform infrared (FTIR) spectra of individual cells acquired using synchrotron and conventional sources. Infrared Phys. Technol. 45, 118-331. 

The situation, however, is different for the infrared spectroscopic measurements with opposed anvil cells. The source beam in commercial Fourier transform infrared spectrometers is generally focused to about 1 cm diameter at the sample, whereas the diameter of the gasket hole in the high pressure cell is only about 0.3 mm. Therefore, a source beam condensing system is required in order to obtain infrared spectra with a good signal-to noise ratio. Commercial beam condensers (4X, 6X) could, in principle, be adapted for these purposes. In practice, however, the mirrors of the... 

All infrared spectra were recorded with an IR-PLAN microscope (IR-PLAN is a registered trade mark of Spectra Tech, Inc.) integrated to a Perkin-Elmer Model 1800 Fourier transform infrared (FT-IR) spectrophotometer. The spectrophotometer consisted of a proprietary heated wire source operated at 1050°C, a germanium overcoated potassium bromide beamsplitter, and a narrow-band mercury-cadmium-telluride (HgCdTe) detector. The detector was dedicated to the microscope and had an active area of 250 x 250 pm. The entire optical path of the system microscope was purged with dry nitrogen. 

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