14NH3 Hyperfine Structure and Quadrupole Coupling

Hyperfine structure on the inversion transition for rotational states $\text{J–K\hspace{0.17em}=\hspace{0.17em}2–1, 3–1, 4–2, 4–4,}\mathrm{and}\text{5–5}$ was measured with a high‐resolution beam maser spectrometer. Variations of nitrogen quadrupole coupling strength were observed for different rotational states. Derivatives of quadrupole coupling strength with respect to molecular coordinates are given. Additional spin–spin and spin–rotational terms are present for $\text{K\hspace{0.17em}=\hspace{0.17em}1}$ states. These terms are compared for $\text{J–K\hspace{0.17em}=\hspace{0.17em}1–1, 2–1,}\mathrm{and}\text{3–1}$ states. A more complete specification of the nitrogen and hydrogen spin–rotation tensors is obtained with the new data.