A set of five search routines—absolute difference, absolute derivative, square difference, square derivative, and Euclidean difference—have been applied to the analysis of the matrix isolation/Fourier transform-infrared spectra (MI/FT-IR) of the components of four essential oils: coriander oil, lemon oil, geranium oil, and citronella oil, The routines were tested under a variety of parameters on a diverse set of compounds and IR spectra. Areas of acceptable performance by the routines as well as areas of marginal performance are discussed. Under the conditions of this study, the absolute derivative routine is judged to be the most acceptable of the five.
W. M. Coleman and Bert M. Gordon, "Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds. Part XIV: Evaluation of Library Search Routines for Identification of Essential Oil Components," Appl. Spectrosc. 43, 998-1003 (1989)