Collision-Induced Spectra: An Avenue to Investigate Microscopic-Scale Diffusion in Fluids

W. A. Herrebout, B. J. Van der Veken, A. Kouzov

Research output: Contribution to conferenceAbstract


New data on the IR spectra induced by intermolecular interactions in liquid cryogenic mixtures at T=89 K (O2 in LAr and LN2 and binary O2-Ar solutions in LN2) are reported. The induced fundamental bands appear as diffuse pedestals(with FWHH≈100 cm−1 ) on which weak, paradoxically sharp lines (FWHH≈2 cm−1) develop at the 2326 and 1552 cm−1 frequencies of the free-molecule vibrational transitions in N2 and O2, respectively. In LAr and LN2 these lines were carefully separated and studied at varied O2 concentrations up to c =0.23 mole fractions (mf). While the 1552 cm−1 line scales as c[O2]2 and thus is induced by the O2-O2 interactions in a bulk of cryosolvent (Ar, N2), the 2326 cm-1 feature varies linearly with c[O2] and hence is caused by interaction of a guest (O2) with a vibrating host (N2). The impurity induction mechanism was further supported by our data on the binary O2-Ar solutions in LN2 recorded at the fixed c[O2] (0.03 and 0.06 mf) and the varied c[Ar]≤ 0.2 mf. Both series revealed the same (linear)
Original languageUndefined
StatePublished - 2014
Externally publishedYes
Event69th International Symposium on Molecular Spectroscopy - Urbana-Champaign, United States
Duration: 16 Jun 201420 Jun 2014


Conference69th International Symposium on Molecular Spectroscopy
CountryUnited States
Internet address


  • collision-induced spectra
  • translational motion
  • diffusion

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