The FIR/THz spectral region plays a very important role for the study of inorganic substances which involve vibrations of heavier atoms, since many of their characteristic bands lies below 400 cm-1. Using VERTEX FM functionality for the VERTEX 70-70v FT-IR research spectrometer high quality far IR spectra can be obtained simultaneously with standard MIR spectra without the need of changing any optical components.
An Attenuated Total Reflection (ATR) accessory greatly simplifies the sample preparation in comparison to the traditional polyethylene discs and Nujol mulls in the transmission measurement mode. Bruker’s Platinum ATR accessory with diamond ATR crystal is ideal for the operation in the far IR because of its all reflective optics.
However, ATR spectra show differences in band intensity and position compared to spectra recorded in transmission mode. In the far IR region and with inorganic samples with higher refractive index the phenomena can be more obvious. The OPUS FT-IR software contains an advanced ATR correction function, which enables the comparison of FIR ATR results with reference transmission spectra in the literature.
CaCO3 FIR ATR measurement.
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