On Cross-Correlation of DFT Calculated and Measured IR Absorption Spectra

Comparisons of IR absorption spectra calculated using density functional theory (DFT) and measured IR transmission spectra for three nitrosamines are presented. These nitrosamines are major environmental contaminants. In general, identification of target molecules by cross correlation of spectra can be accomplished using signal templates having patterns associated with known materials. DFT calculated IR spectra can provide reasonable templates for filtering of IR spectral measurements associated with different types of detector schemes and complex spectral-signature backgrounds. The comparisons of spectra presented here demonstrate that DFT calculated IR spectra can be cross correlated with measured spectra to determine the presence of target molecules.