A complete representation of water vapor IR absorption as a function of frequency, partial pressure, and temperature is accomplished by a semiempirical total line shape model. Water vapor dimer models accounting for continuum absorption are found to be unnecessary.
Founded in 1916, the Optical Society of America (OSA) was organized to increase and diffuse the knowledge of optics, pure and applied; to promote the common interests of investigators of optical problems, of designers and of users of optical apparatus of all kinds; and to encourage cooperation among them. The purposes of the Society are scientific, technical and educational.
The Optical Society of America brings together optics and photonics scientists, engineers, educators, and business leaders. OSA's membership totals 15,500 individuals from over 95 countries. Approximately 47% of the Society's members reside outside the United States.
Water continuum CO2 laser absorption spectra are reported for temperatures between 27 and -10°C. The continuum is found to possess a negative temperature coefficient. The results obtained suggest that the magnitude of this temperature coefficient increases with increasing water pressure and decreasing temperature. The temperature coefficients between 27 and 10°C for air mixtures containing 3.0- and 7.5-Torr water vapor are -2.0 ± 0.4 and -2.9 d 0.5%/ C, respectively. For mixtures with 3.0-Torr water the 10-O°C temperature coefficient is -7.7 ± 0.2%/°C. The temperature and water pressure dependencies observed for the continuum suggest that while both collisional broadening and water dimer mechanisms contribute to the continuum, the dimer mechanism is more important over this temperature range.
