High-Resolution Infrared Spectroscopy of the NU2 and 2NU2 Bands of NITROGEN-15 Labeled Ammonia Using a Tunable Diode Laser Spectrometer.

In this work, a diode laser spectrometer is used to study the infrared spectra of isotopic ammonia gas, ('15)NH(,3). The diode laser spectrometer is calibrated in one of two ways for this work, using a heterodyne system for absolute calibration or using an etalon system for relative calibration. In this manner three of the rotation -vibration-inversion subbands of ('15)NH(,3) are measured. These subbands are the a(nu)(,2)-s(nu)(,0), s(nu)(,2)-a(nu)(,0), and s2(nu)(,2)-a(nu)(,2); all of these subbands have absorption lines in the 1000 cm('-1) wavenumber range. The measurements were used to fit polynomial expressions for the molecular Hamiltonians of each subband.