¹⁴NH₃ hyperfine structure and quadrupole coupling

Hyperfine structure on the inversion transition for rotational states J-K=2-1, 3-1, 4-2, 4-4, and 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 K=1 states. These terms are compared for J-K= 1-1, 2-1, and 3-1 states. A more complete specification of the nitrogen and hydrogen spin-rotation tensors is obtained with the new data.