Infrared-microwave two-photon spectroscopy of the ν2 band of 15NH 3

The frequencies of 60 transitions in the ν₂ vibration-rotation band of ¹⁵NH ₃ were measured to an accuracy of ±0.0002 cm ^-1 by the technique of infrared-microwave two-photon spectroscopy. These frequencies were combined with previous two-photon measurements, with diode laser results, with laser Stark data, and with ground-state inversion frequencies to derive rotational constants for the hypothetical inversion-free ground state and to derive effective rotational constants for the s and a components of the v₂ = 1 state.