Abstract.
The structures of 3,3,3-trifluoromethyl ketene and 3,3-difluoromethyl ketene were studied by utilizing ab initio calculations with the 6-311++G** basis set at the (B3LYP) Density Functional level. Full optimization was performed for both molecules in their ground and transition states. Energy optimization of the systems under investigation shows that trifluoromethyl ketene exists only in the cis conformation (fluorine atom eclipses the ketene group). Difluoromethyl ketene was predicted to have two stable conformations: the cis (hydrogen atom eclipses the ketene group) and the gauche (fluorine atom eclipses the ketene group) form. The conformational stability of the molecules was found to be governed mainly by electrostatic and molecular orbital interactions. The vibrational frequencies were computed and complete assignments were provided on the basis of normal coordinate calculations and comparison with similar molecules. The potential energy distributions (PED) among symmetry coordinates were derived for the stable conformations of the two molecules.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 29 March 2001 / Accepted: 28 June 2001 / Published online: 21 September 2001
Rights and permissions
About this article
Cite this article
Förner, W., Badawi, H., Al-Saadi, A. et al. Vibrational assignments and derived potential energy distributions for tri- and difluoromethyl ketene by density functional calculations. J Mol Model 7, 343–353 (2001). https://doi.org/10.1007/s008940100046
Issue Date:
DOI: https://doi.org/10.1007/s008940100046