Absorption spectrum of water vapor between 4.5 and 13 microns

Abstract

The absorption spectrum of water vapor has been measured from 4.5 to 13 microns with a 3600 line per inch replica echelette grating as dispersing element. Various absorbing path lengths and concentrations of water vapor at atmospheric pressure were used up to 8 meters of steam near 110° C. Almost all of the previously unreported lines that have been found are also present in the solar spectrum. A rotational analysis shows that most of the lines can be assigned either to rotational transitions or to rotation-vibration transitions of the v2 fundamental of the water-vapor molecule. In additional, a few lines have also been assigned to the transitions (2v2-v2), (v1-v2), and (v3-v2).