Spectral Emissivities and Integrated Intensities of the 1.87-, 1.38-, and 1.14-μ H2O Bands between 1000° and 2200°K

Abstract

Spectral emissivities of the overtone and combination bands of H₂O in the 1‐ to 2‐μ region have been measured between 1000° and 2200°K. The hot water vapor samples were produced in a small supersonic burner using H₂ and O₂. The measurements were made at the exit of the burner where the interactions of the hot gas jet with the ambient atmosphere are small. The variation of the spectral emissivities of H₂O in the optically thin absorption region as a function of temperature are given for a total pressure of 1 atm and a constant amount of H₂O in the optical path. The integrated intensities of the bands have been determined from the emissivity spectra at the various temperatures. The values of the integrated intensities of the 1.87‐, 1.38‐, and 1.14‐μ H₂O bands at 273.2°K are 26.0, 21.2, and 1.92 (cm^—2·atm^—1), respectively. The integrated intensity variations with temperature of the bands have been used to determine the absolute intensity contributions from the numerous overtone and combination transitions which make up these bands.