Accuracy of the wavenumber scale of spectroscopic instrumentation is fundamentally important for most applications. Most modern Fourier transform spectrophotometers (FTS) incorporate HeNe lasers that are used to set the wavenumber scale for the instrument. The frequency of these lasers is typically known to within 0.01 cm-1. Yet a variety of error sources can result in much larger wavenumber scale errors for actual sample measurements. Hence, a calibration is required to guarantee the accuracy of the wavenumber scale. Wavenumber standards are the primary tool of a spectroscopist or instrument manufacturer for establishing valid wavenumber uncertainty levels and calibration of the scale. A number of standards have been investigated and developed over time, including solid, liquid, and gas phase forms. This article reviews the historical development and current status of wavenumber standards for the mid-infrared. In addition, important aspects of the implementation of the standards for calibration of instruments are also discussed.
Citation: Handbook of Vibrational Spectroscopy
Publisher Info: John Wiley & Son, Hoboken, NJ
Pub Type: Books
calibration, Fourier transform infrared, FT-IR, infrared, spectrophotometry, spectroscopy, wavenumber standards