High-Resolution Study of the C-D Stretching Bands of 12C6D6 and 13C6D6

✍ Scribed by J. Pliva; J.W.C. Johns; L. Goodman

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 515 KB
• Volume: 163
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1994.1011

✦ Synopsis

The perpendicular C-D stretching bands (\nu_{12}) (species (E_{1 u}) ) were measured for two isotopomers of benzene with (D_{6 h}) symmetry, ({ }^{12} \mathrm{C}{6} \mathrm{D}{6}) and ({ }^{13} \mathrm{C}{6} \mathrm{D}{6}), on a high-resolution Fourier transform spectrometer. Both bands show effects of fairly strong perturbations by states resulting from combinations of low-frequency vibrations. The (\nu_{12}) state of ({ }^{12} \mathrm{C}{6} \mathrm{D}{6}) is in Fermi resonance with the combination (\nu_{2}+\nu_{13}) whose ({ }^{p} P) lines, enhanced by the resonance, are observed just below the ({ }^{p} P) branches of (v_{12}). An (x, y)-type Coriolis interaction with an unidentified state of symmetry (E_{2 u}), and another anharmonic interaction with an unknown (E_{1 u}) state, have also been detected in the spectrum. These interactions were included, along with the Fermi resonance and the rotational (l) resonance and -doubling, in the Hamiltonian used in the analysis of this band. For the (\boldsymbol{v}{12}) band of the ({ }^{13} \mathrm{C}{6} \mathrm{D}{6}) isotopomer, a strong perturbation by an anharmonic resonance with the (E{14}) state (\nu_{7}+\nu_{11}+\nu_{14}) and a much weaker perturbation, presumably by a (z)-type Coriolis interaction with an unidentified perturber, have been observed and taken into account in the analysis. Spectroscopic constants are reported for the (\nu_{12}) states of the two isotopic species, and parameters obtained for the various perturbers and coupling constants are also listed. It is found that the (\zeta) sum for the (E_{i u}) vibrations of all (D_{b h}) isotopomers of benzene differs slightly from the theoretical value of (\Sigma \zeta_{t}) (=-1). (c) 1994 Academic Press, Inc