FTIR rapid-scan interferometer

Successful concepts for "reaction-modulated" IR difference spectroscopy use the multiplex advantage of FTIR spectroscopy or the availability of high-intensity laser IR sources. A kinetic photometer using tunable IR diode lasers as sources for the mid-infrared has been developed in our laboratory and will be described elsewhere [6]. It covers the time-domain from approx. 500 nsec to some seconds. A second approach is time-resolved FTIR spectroscopy using a rapid-scanning interferometer, several scans can be recorded per second and the time-domain of slow reactions thus be covered [7]. The following schemes illustrate both concepts ... 

More recently, Weiller (39) has extended this work by performing a detailed rapid-scan FTIR study of M(CO)e (M = Cr or W) in liquid Xe and liquid Kr. A pulsed UV laser source, synchronized to the moving mirror of the FTIR interferometer, was used to photolyze the hexacarbonyls. MCCOsKr was characterized in liquid Kr, Cr(CO)gXe in liquid Xe, and W(CO)sXe in liquid Xe and liquid Kr doped with 5% Xe. M(CO)gKr has... 

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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