Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Calculation of the rotational constants A and C for isotopic species of slightly perturbed CH3CN symmetric top molecules

  • 89 Accesses

  • 1 Citations

Abstract

A technique which was employed earlier to calculate the rotational constants of CH3CCH has been extended to the ground and two vibrational levels in thev 8 vibration of CH3CN for several isotopic species. The moments of inertia and a computer iteration technique over experimental data for each isotopic species were employed to evaluate the constantA v in an excited vibrational state for a symmetric top molecule. This method gave good estimates forA v for each isotope. The angle of bending and the orientation of each molecular system in reference frames, one fixed on the carbon atom at the -C≡N site and the other at the center of mass, were explored. These results are discussed in this paper. The method, which was applied by Tam and Roberts to the nv10,n=1, 2, 3, 4, vibrations of CH3CCH earlier and which was extended to thev 10=1 vibration of CH3CCH with13C isotopic species, has been applied to13C isotopic species of CH3CN and seems to be a useful tool to extract the value ofA 0. Each of these molecules shows reasonable dependency ofA v over vibrational levels. Values ofA v calculated from the geometrical model are in good agreement with those obtained by fitting the terms in the frequency equations, which containedA v , to the experimental data through an iteration technique in which the value ofA was allowed to vary.

This is a preview of subscription content, log in to check access.

References

  1. 1.

    Burger, H.; Schippel, G.; Ruoff, A.; Essig, H.; Cradock, S.J. Mol. Spectrosc. 1968,106, 349–361.

  2. 2.

    Graner, G.; Demaison, J.; Wlodarczak, G.; Anttila, R.; Hillman, J. J.; Jennings, D. E.J. Mol. Phys. 1968,64, 214–224.

  3. 3.

    Duncan, J. L.; McKean, D. C.; Michie, N. D.J. Mol. Struct. 1974,21, 405–410.

  4. 4.

    Tam, H. S.; Roberts, J. A.J. Mol. Spec. 1989,134, 281–289.

  5. 5.

    Kessler, M.; Ring, H.; Trambarulo, R.; Gordy, W.Phys. Rev. 1950,79, 54–56.

  6. 6.

    Trambarulo, R.; Gordy, W.J. Chem. Phys. 1950,18, 1613–1616.

  7. 7.

    Graybeal, J. D.Molecular Spectroscopy, McGraw-Hill: New York, 1988, p. 667.

  8. 8.

    Rhee, W. M.; Roberts, J. A.J. Mol. Spectrosc. 1987,126, 356–369.

  9. 9.

    Dubrulle, A.; Boucher, D.; Burie, J.; Demaison, J.J. Mol. Spectrosc. 1978,72, 158–164.

  10. 10.

    Demaison, J.; Maes, H., Van Eijck, B. P.; Wlodarczak, G.; Lanse, M. C.J. Mol. Spectrosc. 1987,125, 214–224.

  11. 11.

    Lide, D. R. Ed.,Handbook of Chemistry and Physics, 71st ed., CRC Press: Boca Raton, FL, 1990.

  12. 12.

    Koivusaari, M.; Horneman, V-M.; Anttila, R.J. Mol. Spectrosc. 1991,149, 447–457.

  13. 13.

    Chen, Weidong; Bocquet, R.; Boucher, D.; Demaison, J.; Wlodarczak, G.J. Mol. Spectrosc. 1991,150, 470–476.

  14. 14.

    Demaison, J.; Dubrulle, A.; Boucher, D.; Burie, J.J. Mol. Spectrosc. 1979,76, 1–16.

  15. 15.

    Bocquet, R.; Wlodarczak, G.; Bauer, A.; Demaison, J.J. Mol. Spectrosc. 1988,127, 382–389.

  16. 16.

    Hajsaleh, J.; Roberts, J. A. (work in preparation).

  17. 17.

    Wallraff, P.; Yamada, Koichi M. T.; Schieder, R.; Winnewisser, G.J. Mol. Spectrosc. 1985,12, 163–172.

  18. 18.

    Pekkala, K.; Graner, G.; Wlodarczak, G.; Demaison, J.; Koput, J.J. Mol. Spectrosc. 1991,149, 214–229.

  19. 19.

    Private communication from Professor H. D. Rudolph, Department of Physical Chemistry, University of Ulm, Ulm, Germany.

  20. 20.

    Le Guennec, M.; Wlodarczak, G.; Burie, J.; Demaison, J.J. Mol. Spectrosc. 1992,154, 305–323.

  21. 21.

    Gordy, W.; Cook, R. L.Microwave Molecular Spectra, 3rd ed., Wiley: New York, 1984, p. 583.

Download references

Author information

Correspondence to J. A. Roberts.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Al-Share, M., Hajsaleh, J., Qian, S.W. et al. Calculation of the rotational constants A and C for isotopic species of slightly perturbed CH3CN symmetric top molecules. Struct Chem 5, 109–115 (1994). https://doi.org/10.1007/BF02265352

Download citation

Key words

  • Acetonitrile
  • methyl cyanide
  • rovibrational spectra
  • rotational constants
  • microwave spectra
  • v 8 vibration