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Title:14NH3 line positions and intensities in the far-infrared: comparison of FT-IR measurements to empirical hamiltonian model predictions
Author(s):Sung, Keeyoon
Contributor(s):Manceron, Laurent; Kwabia Tchana, F.; Pirali, Olivier; Pearson, John; Yu, Shanshan
Abstract:We have analyzed multiple spectra of high purity (99.5\%) normal ammonia sample recorded at room temperatures using the FT-IR and AILES beamline at Synchrotron SOLEIL, France. More than 2830 line positions and intensities are measured for the inversion-rotation and rovibrational transitions in the 50 – 660 \wn region. Quantum assignments were made for 2047 transitions from eight bands including four inversion-rotation bands (gs(a-s), \nub{2}(a-s), 2\nub{2}(a-s), and \nub{4}(a-s)) and four ro-vibrational bands (\nub{2} – gs, 2\nub{2} – gs, \nub{4} – \nub{2}, and 2\nub{2} –\nub{4}), as well as covering more than 300 lines of $\Delta$K = 3 forbidden transitions. Out of the eight bands, we note that 2\nub{2} – \nub{4} has not been listed in the HITRAN 2012 database. The measured line positions for the assigned transitions are in an excellent agreement (typically better than 0.001 \wn) with the predictions from the empirical Hamiltonian model [S. Yu, J.C. Pearson, B.J. Drouin, et al.(2010)] in a wide range of J and K for all the eight bands. The comparison with the HITRAN 2012 database is also satisfactory, although systematic offsets are seen for transitions with high J and K and those from weak bands. However, differences of 20\% or so are seen in line intensities for allowed transitions between the measurements and the model predictions, depending on the bands. We have also noticed that most of the intensity outliers in the Hamiltonian model predictions belong to transitions from gs(a-s) band. We present the final results of the FT-IR measurements of line positions and intensities, and their comparisons to the model predictions and the HITRAN 2012 database.\footnote {Research described in this paper was performed at the Jet Propulsion Laboratory and California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration.}
Issue Date:2016-06-24
Publisher:International Symposium on Molecular Spectroscopy
Genre:Conference Paper/Presentation
Rights Information:Copyright 2016 by the authors
Date Available in IDEALS:2016-08-22

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