Abstract

A high-resolution interferometer and high-temperature absorption cell have been used in a continuing measurement program of rotation-vibration spectra of the isotopes of carbon dioxide in different spectral regions. This paper covers results for the isotopes ¹³C¹⁶O₂ and ¹⁶O¹³C¹⁸O with band centers in the spectral region 600 to 800 cm^-1.

Only a few experimental details will be given here; additional details may be found in the literature.¹ The experimental components include an infrared source, a radiation chopper, a high-temperature single-pass gas-sample absorption cell, a Michelson interferometer with "cat’s eye" mirrors employing a step-and-integrate mirror motion, and two liquid-helium-cooled detectors. A carbon dioxide gas sample was contained in the 1.75 meter single-pass stainless-steel sample cell. The central one meter section of the cell was maintained at a temperature of 800K, with temperature gradients in the end segments of the cell, ending with the cell windows at room temperature. For this study a stepping mirror displacement of 75 cm was used, giving a resolution (FWHM) of 0.006 cm^-1 with triangular apodization.

© 1992 Optical Society of America