Are Group Frequencies Obsolete?

Abstract

In spite of the diminishing number of publications on the subject, group frequencies remain an important research tool for infrared spectroscopists. The capabilities of FT-IR present us with opportunities for discovering useful new correlations. High-quality conventional spectra, vapor spectra, and matrix isolation spectra are easy to obtain. Large libraries of FT-IR spectra are being generated and made available in digital form for fast library searching. Computerized spectrum interpretation is becoming a reality. All these applications, for best utility, require wavelength accuracy of ±l/cm, and this accuracy is easily obtainable from FT-IR spectrometers. Unfortunately, the need for sample integrity and careful sample handling is often unappreciated and may be the fatal flaw that prevents us from realizing the full potential of the infrared method. Careful sample selection, the use of good sample handling techniques, and evaluation of the resulting spectrum by a knowledgeable spectroscopist can minimize problems. Several examples of the uses of group frequencies accurate to ±l/cm in organosilicon chemistry are given.