Photoacoustic spectroscopy (PAS) has only recently emerged as a tool for the investigation of the vibrational spectra of condensed matter and surface adsorbates. Qualitative infrared (IR) photoacoustic spectra of various solid materials have been reported both dispersively1–5and in the Fourier transform mode.6–11In order to obtain quantitative information from a photoacoustic spectrum (as would be needed to monitor kinetics of surface reactions or for analytical purposes) it is necessary to convert the single beam spectrum into a double beam spectrum by ratioing against the spectral profile of the source radiation as it impinges on the sample. This is called source normalization.