Absorption of Infrared Radiant Energy by CO_2 and H_2O III Absorption by H_2O between 05 and 36 cm^−1 (278 μ−2 cm)*

Abstract

Interferometric techniques have been employed to measure the H2O absorption between approximately 12.6 cm-1 and 36.0 cm-1. The experimental results, along with results obtained between 0.5 cm-1 and 10 cm-1 by other workers, have been compared with calculated values of transmittance based on theoretically determined positions, strengths, widths, and shapes of the absorption lines. From these comparisons it has become apparent that none of the well-known theoretical line shapes are correct for the extreme wings of the H2O lines below approximately 40 cm-1. The amount of continuum absorption which must be added to the theoretical absorption coefficient to provide agreement with the experimental results has been determined for N2- and self-broadened lines. A table of the line parameters has been included, along with a discussion of the procedure to be followed in calculating the transmittance of homogeneous and inhomogeneous paths.