CALCULATION OF ASYMMETRIC ROTOR ENERGIES---APPLICATION TO $H_{2}^{16}O$ AND $H_{2}^{18}O$.

The work pertaining to the $H_{2}^{16}O$ molecule was supported, in part, by the Air Force Cambridge Research Laboratories, Office of Aerospace Research, and the work on the $H_{2}^{18}O$ molecule was supported, in part, by the U. S. Atomic Energy Commission (COO-882-5). $^{1}$ R. A. Hill and T. H. Edwards, J. Mol. Spectroscopy 11, 433 (1963). $^{2}$ J. Dowling, J. Mol. Spectroscopy 6, 550 (1961). $^{3}$ W. S. Benedict, H. H. Classen, and J. H. Shaw, J. Research, NBS 49, 91 (1952).Author Institution: Department of Physics, Laboratory of Molecular Spectroscopy and Infrared Studies, The Ohio State University; Los Alamos Scientific Laboratory, University of CaliforniaThe sum rules for planar asymmetric $molecules^{1}$ are used to get four combination relations involving A,B,C and seven distortion constants which are coefficients of terms quartic in P. They are modified to include the coefficient of one $P^{6}$ term. A, B, C and five distortion constants may be determined graphically if the relations of $Dowling^{2}$ are assumed. Levels calculated from these constants agree with those given by Benedict, et al.$^{2}$ The method is also applied to the ground state of $H_{2}^{18}O$