Line Intensities in the Far-Infrared Spectrum of H2O2

✍ Scribed by A. Perrin; J.-M. Flaud; C. Camy-Peyret; R. Schermaul; M. Winnewisser; J.-Y. Mandin; V. Dana; M. Badaoui; J. Koput

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 313 KB
• Volume: 176
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1996.0089

✦ Synopsis

Using high resolution Fourier transform spectra (resolution 0.002 cm 01 ) recorded at the Instituto Ricerca Onde Electromagnetiche Firenze and at the Justus Liebig University Giessen, it has been possible to measure the relative intensities of lines in the far-infrared spectrum of H 2 O 2 in the 25-400 cm 01 spectral region. These intensities were used as input data in a least-squares fit calculation in order to obtain the expansion parameters of the transition moment operator of the pure torsional-rotational transitions of H 2 O 2 . For these intensity calculations, the theoretical model takes into account the cos g-type dependence of the dipole moment due to the large amplitude motion of the H atoms relative to the O-O bond, where 2g is the torsion angle. The value of the dipole moment obtained from the fit of the observed intensities was then scaled to the value obtained from Stark effect measurements. Finally, a synthetic spectrum of the far infrared band of H 2 O 2 was generated, using the dipole moment expansion determined in this work for the line intensities and the parameters and the Hamiltonian matrix given in a previous analysis (C. Camy-Peyret, J.-M. Flaud, J. W. C. Johns, and M. Noel, J. Mol. Spectrosc. 155, 84-104 (1992)) for the line positions. In addition to the (Dn Å {1, DK a Å |2) torsional-rotational resonances within the ground vibrational state, which are usually observed for H 2 O 2 , the Hamiltonian model takes explicitly into account both the vibration-rotation resonances involving the ground state and the £ 3 Å 1 vibrational state and the ''staggering'' effect which is due to the cis potential barrier.