Abstract

The absorption spectra of the 4.3-μ band was measured at altitudes from 10 to 30 km along slant paths in the atmosphere using the sun as a radiation source. These spectra were obtained by the use of a balloon-borne grating spectrometer having a resolution of 0.5 cm⁻¹. This resolution is high enough to require a line-by-line calculation to interpret the spectra. By making two assumptions it has been possible to calculate spectra (using a small computer) that agree quite well with the observed spectra. The primary approximations used were the assumption of like rotational structure for all isotopes and excited states, and the assumption of constant displacement between the various states of ¹²C and ¹³C. At the higher altitudes the Lorentz broadening theory resulted in a satisfactory agreement between the calculations and the experimental results, but at the lower altitudes use of the empirical modification proposed by Benedict was necessary to obtain agreement in the region of the high-frequency end of the band. The calculations cover the frequencies from 2235 to 2415 cm⁻¹.

© 1965 Optical Society of America

Infrared Transmission of Synthetic Atmospheres.* II. Absorption by Carbon Dioxide

J. N. Howard, D. E. Burch, and Dudley Williams
J. Opt. Soc. Am. 46(4) 237-241 (1956)

Comparison of Experimental and Theoretical Slant Path Absorptions in the Region from 1400 to 2500 cm⁻¹

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Absorption of 3.39-Micron Helium–Neon Laser Emission by Methane in the Atmosphere

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Appl. Opt. 4(12) 1624-1631 (1965)

Absorption by Infrared Bands of Carbon Dioxide Gas at Elevated Pressures and Temperatures*

D. K. Edwards
J. Opt. Soc. Am. 50(6) 617-626 (1960)