It has been reported that the use of an infrared transparent polarizable gas such as xenon enhances the FT-IR photoacoustic signal of some species adsorbed on a sample surface. Diffuse reflectance and photoacoustic FT-IR methods were used to obtain spectra of silica surfaces under helium, nitrogen, and xenon. Absence of the reported effect with both techniques is shown, and a tentative explanation for these results is given.
