Infrared Spectrum of Water Vapor. Part I—The 6.26μ Region

The absorption spectrum of water vapor has been measured from 5.26μ to 7.14μ. The spectra were observed with a Pfund‐type vacuum spectrometer employing a 4500‐line‐per‐inch echelette grating as the dispersing element. Lines separated by intervals of the order of 0.1 cm^‐1 were resolved. The rotational analysis leads to the following molecular constants for the H₂O bending vibration: $$\begin{array}{c}{\nu }_0\text{=1594.78±0.10\hspace{0.17em}\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}\\ \mathrm{A}{\text{=\hspace{0.17em}31.20}}_0\text{±0.01\hspace{0.17em}\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}\\ \mathrm{B}{\text{=\hspace{0.17em}14.67}}_9\text{±0.005\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}\\ \mathrm{C}{\text{=\hspace{0.17em}\hspace{0.17em}9.15}}_0\text{±0.005\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}.\end{array}$$