Rotational Band Analysis of Vibrational Modes 6 and 7 of Benzene Isotopomers Using REMPI and TOF-MS

✍ Scribed by R.J.J.M. Steenvoorden; M.H. Vasconcelos; P.G. Kistemaker; T.L. Weeding

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 522 KB
• Volume: 161
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1993.1213

✦ Synopsis

We present absorption spectra of the rotational band contours of the 60 and (70_{0}^{1}) bands in benzene, ({ }^{12} \mathrm{C}{6} \mathrm{H}{6}) and ({ }^{13} \mathrm{C}^{12} \mathrm{C}{5} \mathrm{H}{6}). These spectra were measured using resonant two-photon ionization in combination with time of flight mass spectrometry. A rotational temperature of (2.0 \mathrm{~K}) was obtained by coexpanding the benzene in a supersonic jet of argon. We have resolved different (J) levels in the (6{ }_{0}^{1}) band. Contours of the bands are simulated using a rigid-rotor model and accounting for Coriolis splitting. For the isotopomer, the vibrational modes 6 and 7 each consist of two nondegenerate modes (a) and (b) and the positions of these band origins relative to the band origin of the twofold degenerate state of benzene have been determined. The splitting between bands of mode 6 is in good agreement with values reported in literature which were calculated with force field methods for the ground state. The splitting in band 7 is dominated by either a difference in anharmonicity or a shift due to a Fermi resonance. c 1993 Academic Press. Inc.