Induced infrared emission of opaque adsorbents

In a study of infrared spectra of chemisorbed gases, variations in the intensities of the absorption bands of the solid adsorbents were observed in the presence of different gases. This behavior was most pronounced for the most opaque samples. This phenomenon has been related to sample emission arising from sample heating by the spectrometer source, and differences in the thermal conductivities of the gases present. Infrared absorption bands of silica adsorbents were influenced by surface hydroxyl groups, as the bands for silica with deuterated hydroxyl groups differed from those of ordinary silica.