HIGH RESOLUTION INFRARED SPECTRUM OF THE WATER VAPOR MOLECULE AND ITS ISOTOPIC SPECIES.

Author Institution: Laboratory of Molecular Spectroscopy and Infrared Studies, Department of Physics, The Ohio State University; Los Alamos Scientific Laboratory, University of CaliforniaThe spectrum of $H_{2}^{16}O$ and $H_{2}^{18}O$ from 3350 to $4020 cm^{-1}$ has been measured and most of the transitions due to $H_{2}^{18}O$ have been assigned. Four bands, the $\nu_{1}$ and $\nu_{2}$ bands of $H_{2}^{16}O$ and $H_{2}^{18}O$, constitute the greater part of the transitions occurring in, the region. One of the most interesting aspects of these two bands is the interaction of their upper state rotational levels. No previous laboratory measurements have been reported on the $\nu_{1}$ and $\nu_{2}$ bands of $H_{2}^{18}O$ specifically. The use of high-speed computers has made it possible to perform the large distortion corrections occurring in the water molecule in addition to the usual difficult calculations encountered in solving for the energies of asymmetric molecules. The (100)-(001) rotational interaction has been satisfactorily explained. Computer programs have been written to diagonalize and calculate expectation values for the operators of the Hamiltonian matrix of the ground state and the combined upper states. The results of this research will be discussed in relation to the extensive studies made by Dr. W. S. Benedict and others. This work was supported, in part, by the United States Atomic Energy Commission and by the Air Force Cambridge Research Laboratories, Office of Aerospace Research