Isabelle Kleiner

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Cooperativity between weak hydrogen bonds can be revealed in molecular clusters isolated in the gas phase. Here we examine the structure, internal dynamics, and origin of the weak intermolecular forces between sevoflurane and a benzene molecule, using multi-isotopic broadband rotational spectra. This heterodimer is held together by a primary C-H⋅⋅⋅π(More)
Using FT spectra (Bruker IFS 120, unapodized FWHM resolution ≈ 0.001 cm −1) of methyl bromide CH 3 Br, absolute line positions and intensities, as well as self-and N 2-broadening coefficients have been measured for about 1200 lines, between 880 and 1050 cm −1 , in the 6 ν band of both 12 CH 3 79 Br and 12 CH 3 81 Br isotopologues. An absolute wavenumber(More)
The data incorporated in the HITRAN database for 14 NH 3 are analyzed using a comprehensive and consistent set of quantum numbers, empirical lower energy levels and the BYTe variationally calculated line list as reference points. Labelings are checked to ensure that they obey both the usual selection rules and the HITRAN labeling formalisms; the problems(More)
The 6.7 and 12.2 GHz masers, corresponding to the 5(1) → 6(0)A+ and 2(0) → 3(-1)E transitions in methanol (CH3OH), respectively, are among the brightest radio objects in the sky. We present calculations for the sensitivity of these and other transitions in the ground state of methanol to a variation of the proton-to-electron mass ratio. We show that the(More)
This work deals, for the first time, with the modeling of absolute line intensities in the fundamental ν 2 and ν 5 bands of CH 3 79 Br and CH 3 81 Br at 7 µm. For that, four unapodized absorption spectra of CH 3 Br (natural abundance, 99% purity, P×L = 0.082–0.165 atm×cm, room temperature) were measured in the range 1260–1560 cm-1 , at a resolution of 0.002(More)
We determine the sensitivity to a possible variation of the proton-to-electron mass ratio μ for torsion-wagging-rotation transitions in the ground state of methylamine (CH 3 NH 2). Our calculation uses an effective Hamiltonian based on a high-barrier tunneling formalism combined with extended-group ideas. The μ dependence of the molecular parameters that(More)
In this paper we describe the first quantitative search for several molecules in Titan's stratosphere in Cassini CIRS infrared spectra. These are: ammonia (NH3), methanol (CH3OH), formaldehyde (H2CO), and acetonitrile (CH3CN), all of which are predicted by photochemical models but only the last of which has been observed, and not in the infrared. We find(More)
Torsion-rotation transitions in molecules exhibiting hindered internal rotation possess enhanced sensitivities to a variation of the proton-to-electron mass ratio. This enhancement occurs due to a cancellation of energies associated with the torsional and rotational degrees of freedom of the molecule. This effect occurs generally in every internal rotor(More)
The microwave spectrum of linalool, an acyclic monoterpene, was recorded for the first time in the range from 9 to 16 GHz. The only conformer observed under molecular beam conditions was assigned. Fitting the rotational spectrum with two different programs treating internal rotation yielded the rotational constants A = 1.64674020(46) GHz, B = 0.68219862(16)(More)
Recently, methanol was identified as a sensitive target system to probe variations of the proton-to-electron mass ratio μ [Jansen et al. The high sensitivity of methanol originates from the interplay between overall rotation and hindered internal rotation of the molecule; that is, transitions that convert internal rotation energy into overall rotation(More)