Infrared absorption by the water vapor continuum near 1200 cm-1 has been measured with a lead-tin-telluride diode laser over a 40.5-m optical path. The measurements were made as a function of temperature from 333 K to 473 K; thus, they overlap and extend previous measurements made at temperatures between 293 K and 388 K. Over the entire temperature range studied here, the continuum extinction coefficient increases quadratically with water-vapor partial pressure as expected for the relatively high partial pressures used in these measurements. At temperatures below 398 K. our measured extinction coefficients agree well with previously reported data. At higher temperatures, however, the extinction coefficient is almost independent of temperature and is substantially larger than predicted by empirical formulas. Values of the self-broadening coefficient for water vapor have been extracted from the experimental data, and a possible interpretation of the results involving both dimer and line-broadening effects is presented.
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.
