Fourier transform infrared spectroscopy without an FTIR spectrometer: library searching and concise storage of spectra

By use of a dispersive infrared spectrophotometer and a minicomputer for data collection and manipulation, a library of liquid and solid sample infrared spectra was constructed by storing FFT data. A library search routine, which compares signs of cosine and sine FFT terms, discriminates between functional groups reasonably well. Accurate matches of spectra have correlation index (CI) values of about 0.9 with a standard deviation of 0.04. The computer can search 255 spectra in less than 2 min. One 8-in. 0.5-MB floppy disk can store 488 spectra. All programming was done in BASIC