15min:

F. KELLER, A. PERRIN, J.-M. FLAUD, Laboratoire de Photophysique Moléculaire, CNRS, Université Paris Sud, Campus d'Orsay, Bat 210, 91405 Orsay Cedex, France; J. W. JOHNS AND ZHENGFANG LU, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, KIA OR6, Canada; E. C. LOOI, Department of Physics, Faculty of Science, National University of Singapore, Lower Kent Ridge Road, Singapore, 119360 Singapore.

The analysis of the ₆, ₇, ₈ and ₉ bands of H¹⁵NO₃ located at 646.9641, 578.4719, 743.6166 and 458.2917cm^-1 respectively has been carried out in the 400-800cm^-1 region using high resolution Fourier transform spectra recorded at Ottawa. Using the ground state energy levels calculated from the v=0 rotational constants of H¹⁵NO₃ , it was possible to assign the A-type ₆ and ₇ bands and the C-type ₈ and ₉ bands of H¹⁵NO₃ up to high J and K_a rotational quantum numbers. The v₆=1, v₇=1, v₈=1 and v₉=1 experimental energy levels were then introduced in a least squares fit calculation and precise upper state Hamiltonian constants (band centers and rotational constants) were determined allowing one to reproduce the infrared data to within the experimental uncertainty.