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) clu sters (n = 4-8) are calculated in a nonrelativistic approximation of the Ha rtree-Fock-Roothaan method. The calculated frequencies of the totally symme tric stretching vibrations v(S) are in satisfactory agreement with the expe rimental data. The values of v(S) are very sensitive to minor changes in cl uster geometry and to the outer-spheric environment. The high stability of the [ZrF6](2-) ion was confirmed in an MP2 calculation.