Optoacoustic spectroscopy of C2H4 at the 9- and 10-microm C12O216 laser wavelengths.

Absorption coefficients have been measured for ethylene in the 9- and l0-microm range with a photoacoustic spectrophone. Pressure dependency in the 10P C(12)O(2)(16) range was studied for various concentrations of ethylene. Comparisons of the data with other measurements of both atmospheric and pressure-dependent absorption coefficients were also made, and a method for relating ethylene pressure-dependency data on absorption to molecular structure was examined. Typical discrepancies between up to six independent measurements of ethylene absorption were 38.1% at the 10-microm R(20) line, 4.4% at the 10-microm P(18) line, and 18.5% at the 10-microm P(26) laser line.