Rapid scan FTIR mode

Since modern FTIR spectrometers can operate in a rapid scan mode with approximately 50 ms time resolution, TRIR experiments in the millisecond time regime are readily available. Recent advances in ultra-rapid scanning FTIR spectroscopy have improved the obtainable time resolution to 5 ms. Alternatively, experiments can be performed at time resolutions on the order of 1-10 ms with the planar array IR technique, which utilizes a spectrograph for wavelength dispersion and an IR focal plane detector for simultaneous detection of multiple wavelengths. ... 

P 26] Time-resolved FTIR spectroscopy was performed by operation of an infrared spectrometer in the rapid scan acquisition mode (see Figure 1.59) [110]. The effective time span between subsequent spectra was 65 ms. Further gains in time resolution can be achieved when setting the spectral resolution lower (here 8 cm4) or by using the step-scan instead of rapid-scan mode. 

A new and efficient mode of operation is presented that involves a continuous rapid-scan FTIR spectrometer, the measurement technique relying completely on the utilisation of the digital signal processor for data acquisition and manipulation. Experimental and mathematical details were discussed. Application of the rapid-scan technique was illustrated with some results for a styrene-acrylonitrile/butadiene copolymer. 17 refs. 

Because modem FTIR spectrometers can operate in a rapid scan mode with approximately 10 ms time resolution, TRIR experiments in the millisecond... 

Figure 7.45. Potential-difference unpolarized ATR-SEIRA spectra of 4-mercaptopyridine (PySH) SAM on 20-nm-thick (80-nm-size particles) Au evaporated electrode in 0.1 M HCIO4. Reference potential was -0.1 V (SCE). Arrows show changes of peaks for positive shift of electrode potential from -0.3 to -1-0.4 V. Spectra were recorded using Bio-Rad FTS 60A/896 FTIR spectrometer equipped with dc-coupled MCTdetector and bandpass optical filter transmitting between 4000 and 1000 cm". Spectrometer was operated in rapid-scanning mode and spectra were collected sequentially during potential sweep at 5 mV s". Sixty-four interferograms were coadded to record each spectrum, which required about 10 s. Reprinted, by permission, from K. Ataka, Y. Hara, and M. Osawa, J. Electroanal. Cham. 473, 34 (1999), p. 37, Fig. 3. Copyright 1999 Elsevier Science S.A.

In routine FTIR spectroscopy the spectrometer is operated in continuous scan mode. In this mode of operation, the moving mirror is scanned at a constant velocity, v (cms ), with the light beam path difference at any time, t being given hy 6 = 2 1 (cm). An internal HeNe laser beam is also passed through the interferometer and, since it is essentially monochromatic (I5,798cm ), it is used to accurately calibrate the positions of Mm for data sampling. Continuous scan FTIR is most commonly used to monitor stable samples, but can also be used in rapid-scan mode to monitor time-dependent processes on timescales down to ca. 20 ms. 

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