Specifications for Infrared Reference Spectra of Molecules in the Vapor Phase

Infrared spectrometry is being used to an increasing extent for the qualitative and quantitative analysis of trace components of the atmosphere. Several collections of reference spectra of samples in the vapor phase at ambient temperature are now available. The spectra in these collections are measured at medium resolution (Δν = 1 to 4 cm−1); in some the samples are neat at low pressure while in others an atmosphere of air or nitrogen has been added. Although these reference data are certainly useful to the many users of medium resolution spectrometers (both grating and Fourier transform), the spectra have been measured at too high resolution to provide even semiquantitative calibration factors for users of selective wavelength analyzers and at too low resolution for users of tunable diode laser (TDL) spectrometers. There is now a very definite need for collections of spectra of samples in the vapor phase, measured at a variety of resolutions, with and without air broadening, in as uniform a format as possible.