Analysis of Skeletal Deformation Vibration Spectra in Relation to the Molecular Structure

Deformation vibrations associated with displacements of skeletal heavy atoms are mainly discussed. It is shown that skeletal deformation vibrations are sensitive to the change of an azimuthal angle θ and that the frequencies of the vibrations are specific for the structure of rotational isomers. The θ-dependency of skeletal deformation vibrations corresponds exactly to that of elements of a kinetic energy matrix . The results emphasize the simplicity and the usefulness of the approximate normal coordinate treatment in which only skeletal heavy atoms are taken into account.