Preliminary analysis of CH3D from 3250 to 3700cm−1

Abstract

The infrared spectrum of CH3D from 3250 to 3700 cm =1 was studied for the rst time to assign transitions involving the ν2+ν3, ν2+ν5, ν2+ν6, ν3+2ν6 and 3ν6 vibrational states. Line positions and intensities were measured at 0.011 cm =1 resolution using Fourier transform spectra recorded at Kitt Peak with isotopically enriched samples.Some 2852 line positions (involving over 900 upper state levels) and 874 line intensities were reproduced with RMS values of 0.0009 cm =1 and 4.6%, respectively. The strongest bands were found to be ν2 + ν3 at 3499.7 cm =1 and ν2 + ν6 at 3342.5 cm =1 with integrated strengths, respectively, of 8.17 Ö 10 =20 and 2.44 Ö 10 =20 (cm =1 /molecule · cm =2 ) at 296 K (for 100% CH3D). The eective Hamiltonian was expressed in terms of irreducible tensor operators and adapted to symmetric top molecules. Its present conguration in the MIRS package permitted simultaneous consideration of the four lowest polyads of CH3D: the Ground State (G.S.), the Triad from 6.3 to 9.5 mm, the Nonad from 3.1 to 4.8 mm and now the Enneadecad (19 bands) from 2.2 to 3.1 mm. The CH3D line parameters for this interval were calculated to create a new database for the 3 mm region.

CLOUD AND HAZE IN THE WINTER POLAR REGION OF TITAN OBSERVED WITH VISUAL AND INFRARED MAPPING SPECTROMETER ON BOARDCASSINI

“…In any case, the fit at 2.0 μm is poor in quality. The window at 2.8 μm is very complicated because deuterated methane absorbs in the middle of the window (Nikitin et al 2006), optical constants of aerosols have a strong variation between 2.4 and 3 μm (Rannou et al 2010), and finally an absorption feature is missing in the model at 2.75 μm. The 2.8 μm window is extremely interesting because it contains much information and, moreover, is one of the clearest windows.…”

The HITRAN2012 molecular spectroscopic database

“…Finally, the list described here is tailored for Earth remote sensing and will be inadequate to interpret high-temperature spectra (e. g. Thievin et al [145] This prediction was based on the position analysis by Ulenikov et al [152] and employed the transition-moment parameters of the 12 CH 3 D isotopologue from Brown et al [153]. Six new 12 CH 3 D vibrational bands were also added in the near -IR, using the analyzed positions and line intensities of ν 2 + ν 3 , ν 2 + ν 5 , ν 2 + ν 6 , ν 3 + 2ν 6 and 3ν 6 at 2.9 μm by Nikitin et al [154] and empirical measurements of 3ν 2 at 1.56 μm reported by Boussin et al [155]. The values for γ air and γ self were generally obtained using empirical formulae obtained from 12 CH 3 D triad measurements [1,156].…”

Global modeling of the lower three polyads of PH3: Preliminary results

“…A detailed description of the main theoretical features can be found in the original paper [10] and in subsequent reviews [14,25]. This approach has been already successfully applied to complex band systems of symmetric top molecules like CH 3 D [26,27,28] and CH 3 Cl [29,30]. Only basic or original features with respect to previous works will be repeated or detailed here.…”