Advantages and disadvantages of the IES technique. The major advantage of the IES technique is the ability to obtain spectra at the elevated temperatures in situ. This avoids the problems associated with the use of KBr pellets and heating of the pellets to elevated temperatures where reactions between the KBr and the for example clay may occur. The experiment whereby a sample is heated to an elevated temperature and then rapidly cooled to ambient is also not suitable as any reversible phase changes would not be observed. It has been shown that emission spectra are the same as the absorption spectra although some intensity differences in the bands are observed.
Bands are generally broader in the emission spectra.
Selection rules for emission and absorption spectroscopy are identical. Another major advantage is that the hot sample itself is the source and so no instrumental thermal source is required. One difficulty of the technique is the inability to use thick samples. The technique depends upon having a thin film or fine dispersion of a powdered sample on the platinum plate. Such a difficulty may be overcome by reducing the amount of sample or by making the film thinner.