THE PERFORMANCE OF A SMALL, GRATING, INFRARED SPECTROMETER IN THE REGION FROM 2 TO $25\mu$

Author Institution: Department of Chemistry, Purdue UniversityA small, versatile, infrared spectrometer has been constructed (Perkin-Elmer Corporation) which eliminates the unwanted radiation by means of a fore-prism monochromator already described (E. Siegler, Jr. and J. Huley). Separation of the various orders is facilitated by good optical imagry in the fore-prism monochromator and the ready exchangeability of prisms. A cooled, lead telluride cell and a thermocouple have been employed with a Perkin-Elmer monochromator suitably modified for the use of gratings and these detectors. Bausch and Lomb gratings blazed for the first order at $6\mu, 12\mu$ and $112\mu$ have been used to date. The separation of the wavelengths obtained with the fore-prism monochromator makes it possible to use these gratings in the higher orders with case. The performance of the instrument has been tested with water vapor, ammonia, hydrogen bromide, etc. Good wavelength accuracy and resolution of $0.3 cm^{-1}$ or better have been obtained except at the longer wavelength end of the accessible region where suitable gratings are not yet available to us. Typical results observed for $CD_{3}F, CD_{2}HF, NF_{3}, CF_{4}, Co(CO)_{4}H$, etc. will be presented