A vacuum infrared interferometric system for use to 5 cm−1 is outlined. Examples given include high resolution vibrational spectra of some gases.
J. P. Covey, D. G. Mead, and D. R. Mattson, "A High Resolution Vacuum Fourier Transform Far Infrared Spectrometer," Appl. Spectrosc. 34, 165-166 (1980)