Water Vapor-Nitrogen Absorption at CO2 Laser Frequencies.

In this paper we report the results of a series of pressure-broadened water vapor absorption measurements at 27 CO2 laser frequencies between 935 cm−1 and 1082 cm−1. Both multiple traversal cell and optoacoustic (spectrophone) techniques were utilized together with an electronically stabilized cw CO2 laser. Comparison of the results obtained by these two methods shows remarkable agreement, indicating a precision which has not been previously achieved in pressure-broadened studies of water vapor. The data of 10.59 μm substantiate the existence of the large (>200) self-broadening coefficients determined in an earlier study by McCoy. In this work we have treated the case of water vapor in N2 at a total pressure of 1 atm. We have also studied water vapor in air and will report those results separately.