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The transfer functions of infrared spectrometers for incoherent illumination are determined using a lamellar grating interferometer. The spectrometer is illuminated with incoherent radiation and the spectral distribution S (v-v sub 0) of its output radiation.

Experimental testing of the dual-input dual-output operation of the AFGL two-meter path difference interferometer is described, together with the results. It has been found that the external modulation scheme for the interferometer is poorly suited for good suppression. The reasons supporting this conclusion are presented. (Author).

This report describes results obtained with an interferometer spectrometer of the absorption spectrum of CO2 at a temperature of 625 K. The hot cell used in the measurements is described in detail and low resolution emission data (2/cm) of CO2 at around 500 K are presented. The absorption spectrum from 3500 to 3770/cm of CO2 at 625 K to a resolution of 0.01/cm is presented as well as a simulated spectrum computed using the AFGL line compilation. (Author).

This report describes the high-resolution Fourier spectroscopy measurement technique being used at AFCRL. It deals mainly with noise problems of measurement, the noise compensation scheme, and the interferogram signal-detection scheme. The spectral data presented to demonstrate performance of the instrument were obtained with a resolution of 0.0075/cm.

In a recent paper, the author obtained the approximate solution useful to describe the equivalent width of two overlapping lines. G.N. Plass criticized that the error arising in our calculation of some cases for complete overlapping was rather large.

The Idealab 2-m path-difference interferometer was used to obtain data of CH4 in the 1/2700 to 1/3200 cm region to a resolution of 1/.006 cm. Obtained spectral data are presented as well as the results of analysis to calculate line positions and strengths. A comparison of the present data with previously obtained data is also presented. The results of this study are tabulated using the format of the AFGL atmospheric line compilation. (Author).

The CO2 vibrational-rotational transition in the 4.3-micrometers region (2200 to 2400/cm) was observed at an elevated temperature of 600 K. The technique of Fourier spectroscopy was used to observe the spectrum with a resolution of 0.006/cm. The identified lines are expressed in terms of the molecular constants determined through the least-square-error fitting method.

This is an interim report on the progress in the development of a high-resolving power interferometer to be used for line shape measurements. An interferometer is described in detail, as well as the data handling and processing schemes used. A resolution of 0.06/cm was obtained with the instrument operating out in the open with little concern for vibration isolation. Test results are included. (Modified author abstract).