Line positions and intensities of the phosphine (PH₃) Pentad near 4.5μm

Journal Article · Tue Apr 01 04:00:00 EDT 2014 · Journal of Molecular Spectroscopy

DOI:https://doi.org/10.1016/j.jms.2014.01.013· OSTI ID:1133214

Malathy Devi, V.; Kleiner, Isabelle; Sams, Robert L.; Brown, Linda R.; Benner, D. Chris; Fletcher, Leigh N.

In order to improve the spectroscopic database for remote sensing of the giant planets, line positions and intensities are determined for the five bands (2ν₂, ν₂ + ν₄, 2ν₄, ν₁ and ν₃) that comprise the Pentad of PH₃ between 1950 and 2450 cm^-1. Knowledge of PH₃ spectral line parameters in this region is important for the exploration of dynamics and chemistry on Saturn, (using existing Cassini/VIMS observations) and future near-IR data of Jupiter from Juno and ESA’s Jupiter Icy Moons Explorer (JUICE). For this study, spectra of pure PH₃ from two Fourier transform spectrometers were obtained: (a) five high-resolution (0.00223 cm^-1), high signal-to-noise (~1800) spectra recorded at room temperature (298.2 K) with the Bruker IFS 125HR Fourier transform spectrometer (FTS) at the Pacific Northwest National Laboratory (PNNL), Richland, Washington and (b) four high-resolution (at 0.0115 cm^-1 resolution), high signal-to-noise (~700) spectra recorded at room temperature in the region 1800–5200 cm^-1 using the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory (NSO) on Kitt Peak. Individual line parameters above 2150 cm^-1 were retrieved by simultaneous multispectrum fittings of all five Bruker spectra, while retrievals with the four Kitt Peak spectra were done in the 1938–2168 cm^-1 range spectrum by spectrum and averaged. In all, positions and intensities were obtained for more than 4400 lines. These included 53 A+A- split pairs of transitions (arising due to vibration–rotation interactions (Coriolis-type interaction) between the ν₃ and ν₁ fundamental bands) for K" = 3, 6, and 9. Over 3400 positions and 1750 intensities of these lines were ultimately identified as relatively unblended and modeled up to J = 14 and K = 12 with rms values of 0.00133 cm^-1 and 7.7%, respectively. The PH₃ line parameters (observed positions and measured intensities with known quantum assignments) and Hamiltonian constants are reported. Finally, comparisons with other recent studies are discussed.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1133214
• Report Number(s): PNNL-SA-103021; 2149a
• Journal Information: Journal of Molecular Spectroscopy, Journal Name: Journal of Molecular Spectroscopy Journal Issue: C Vol. 298; ISSN 0022-2852
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

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Environmental Molecular Sciences Laboratory