Happiness is a Class II Spectrum

In 1967, the Coblentz Society and the American Society for Testing Materials jointly initiated a pilot project to generate a limited number of research quality (class II) infrared reference spectra. Six infrared laboratories participated, each producing 25 spectra from samples selected from a group of 57 authentically pure chemical compounds. Three of the compounds were run by all laboratories in order to provide a basis for comparison and evaluation. This paper reports the results of the project. Points covered include a discussion of why class II spectra are important to the future of infrared spectroscopy; some of the difficulties encountered by the participating laboratories and ways of overcoming these difficulties; and a critical comparison of spectra from the same compounds produced on different spectrometers and under different sampling conditions.