Abstract

The absorption spectrum of water vapor has been measured from 4.5 to 13 microns with a 3,600 line per inch replica echelette grating as the dispersing element. Various absorbing path lengtns and concentrations of water vapor at atmospheric pressure were used up to 8 meters of steam near 110° C. Almost all of the previously imreported lines that have been found are also present in the solar spectrum. A rotational analysis shows thgifc 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 addition, a few lines have also been assigned to the transitions (2* — V2), (Vi — 2), and . (vz — v%).