Additional Rotational Energy Levels ofH2O andD2O Molecules

An extension of the pure rotational energy levels for ${\mathrm{H}}_2$O and ${\mathrm{D}}_2$O is made in order to obtain new possible microwave transitions. For ${\mathrm{H}}_2$O the levels are given through $J=14\mathrm{}$ and for ${\mathrm{D}}_2$O through $J=15\mathrm{}$. Additional assignments are made in the previously observed absorption spectra. The Wang secular determinant for the asymmetric rotator is expanded, and equations for the energy levels of $J=12\mathrm{}$, 13, 14, and 15 are given in terms of the asymmetry parameter.