Ab initio study of the structure and vibrational spectra of ZrFn4-n systems

The optimal geometry and vibrational spectra of a series of [ZrFn](4-n) clusters (n = 4-8) are calculated in a nonrelativistic approximation of the Hartree-Fock-Roothaan method. The calculated frequencies of the totally symmetric stretching vibrations v(S) are in satisfactory agreement with the experimental data. The values of v(S) are very sensitive to minor changes in cluster geometry and to the outer-spheric environment. The high stability of the [ZrF6](2-) ion was confirmed in an MP2 calculation.