The data on the inversion spectrum in the ν2 state of 14ND3 [F. Scappini, A. Guarnieri, and G. DiLonardo, J. Mol. Spectrosc. 95, 20–29 (1982)] have been extended by measuring frequencies of 25 new transitions. A simultaneous least-squares analysis of these data with the ground state microwave transition frequencies and the diode laser measurements of the ν2 band has been carried out. Improved sets of molecular parameters have been obtained for 14ND3 and 15ND3, including the ground and ν2 state inversion splittings, ν2 band origins, rotational and centrifugal distortion constants, and the parameters of the Δk = ±3n vibrational-rotational interactions.

The inversion spectrum of 15ND3 in the v2 = 1 state was investigated in the millimeter wave region between 70 and 125 GHz. The inversion splitting (J = 0, K = 0) was calculated to be 97 279.998(35) MHz. The K = 3 splitting constants and the electric dipole moment have also been determined.