title: Gas-phase infrared spectra of three compounds of astrochemical interest: vinyl, allenyl, and propargyl isocyanides.
abstract: Isocyanides, isomers of the cyanides detected in the interstellar medium, are also possible components of this medium. The infrared spectra (5000-500 cm(-1) ) of gaseous vinyl isocyanide, allenyl isocyanide, and propargyl isocyanide have been recorded at 0.1 cm(-1) resolution. When prepared on a gram scale to produce a partial pressure of 10 mbar after evaporation in the cell, these three isocyanides, which have previously been reported to be kinetically unstable, do not display any sign of decomposition when recording the spectra. Geometry optimizations and harmonic and anharmonic vibrational frequencies were calculated using the LCCSD(T) method with the cc-pVTZ basis set. Anharmonic frequencies of fundamental, overtone, and combination transitions were calculated using a variational approach implemented in the P Anhar.v2.0 code, to assign the experimental data for each compound. These results improve our knowledge of these under-investigated compounds and pave the way for other physicochemical studies on functionalized isocyanides.
authors.affiliation: Institut de Physique de Rennes, CNRS UMR 6251, Université de Rennes1, 35042 Rennes (France). benidar@univ-rennes1.fr.
authors.forename: Abdessamad
authors.initials: A
authors.lastname: Benidar
authors.forename: Didier
authors.initials: D
authors.lastname: Bégué
authors.forename: Falk
authors.initials: F
authors.lastname: Richter
authors.forename: Claude
authors.initials: C
authors.lastname: Pouchan
authors.forename: Mohammed
authors.initials: M
authors.lastname: Lahcini
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Guillemin
keywords: IR spectroscopy; computational chemistry; density functional calculations; interstellar compounds; isocyanides