VIBRATIONAL ANALYSIS OF CHLORINATED PARA-BENZOQUINONES - TRANSFERABLE FORCE-FIELD FOR IN-PLANE VIBRATIONS

The force field for the in-plane vibrations of p-benzoquinone, its chloro-derivatives and the corresponding fully deuterated analogs is determined using the overlay technique. A 32-parameter modified internal valence force field (MIVFF) is derived from the 290 observed frequencies of the 14 molecules studied. The mean deviation of the calculated wavenumbers from the observed is 5.9 cm-1 or 0.93%. A description of the vibrational modes of the chlorinated p-benzoquinones in terms of the potential energy distribution and cartesian eigenvectors is made available. The given force field extends to the p-quinoid structure the logical frame built up by the force fields available for similar structures as chlorinated benzenes. © 1979.