PNNL

Abstract

Two FTIR intensity artifacts have been observed at moderately high (0.1 cm-1) spectral resolution, 1) light reflected off the aperture back was double modulated by the interferometer productin a 2f alias and 2) the warm (~310 K) annulus of the aperture seen by a cooled detector resulted in both distorted line shapes and anomalous intensities in the fingerprint region. Although the second artifact has been alluded to before, we report corrections to remove both anomalies and demonstrate the efficacy of these corrections. Prior to correction, integrated band intensities were found to be in error by up to 12%. Presumably all medium resolution (