A simultaneous analysis of the microwave, submillimeterwave, and infrared transitions between the ground and ν2 inversion-rotation levels of 15NH 3
The submillimeterwave spectra of the pure inversion and inversion-rotation transitions in the ν2 excited state (79 transitons) and the diode laser spectra of the ν2 band (83 transitions) of 15NH 3 have been measured. A simultaneous least squares analysis has been carried out of these data together with previously published wavenumbers of the pure inversion transitions and inversion-rotation transitions in the ground state measured by the microwave and Fourier spectroscopy, and the ν2 band transition frequencies obtained by the infrared-microwave two-photon technique. A theory of the ∆k = ±3 n interactions in the ground and ν2 excited states of ammonia (Š. Urban, V. Špirko, D. Papoušek, J. Kauppinen, S. P. Belov, L. I. Gershtein, and A. F. Krupnov, J. Mol. Spectrosc.88, 274-282 (1981)) has been used in the analysis. The "smoothed" values of the ν2 band wavenumbers can be used for calibration purposes with better than 1 × 10 -3 cm -1 precision.