Knowledge Bank

Precise values for ground state energy levels of $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}NH3$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">15</mrow>}NH3$ were obtained from extensive sets of experimental data. Microwave, submillimeter wave pure inversion transitions in the ground and $\nu 2$ states, far IR inversion-rotation transitions in the ground state and vibration-rotation transitions in $\nu 2$ band (measured by two-photon, laser Stark, FTS, and diode laser heterodyne techniques) were simultaneously processed together with all forbidden transitions by the method of least squares. This extensive data set completely describes the energy levels for all possible quantum numbers K, including the spacing of the levels with different K, up to $J=17$, for both $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}NH3$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">15</mrow>}NH3$. Various approximations of parametrization have been used.