ABSTRACT
Class II spectra are reference spectra obtained on the best currently available commercial infrared grating spectrophotometers, operated at maximum efficiency under conditions consistent with acceptable laboratory practice. The purity of the compounds should be rigidly specified with respect to the type and quantity of any impurity detectable in the spectroscopic measurements. The specifications for Class II spectra given in this report apply only to the absorption spectra of condensed phase systems, and it is not considered practical to write specifications for vapor phase spectra or for reflectance spectra at this time.
