RAMAN AND IR SPECTROSCOPY OF (GEO)(N), WITH N=1,2,3,4, ISOLATED IN SOLID ARGON

Raman and IR spectroscopy of GeOn, with n=1,2,3,4, isolated in solid A r were used for the elucidation of the corresponding molecular structu res. The experiments were complemented by extensive ab initio calculat ions at different theoretical levels, in the case of Ge2O2 additionall y by normal-coordinate analysis. The assignment of a planar, cyclic D- 2h symmetric structure to Ge2O2, made formerly on the basis of IR spec troscopic investigations, was confirmed. It was possible to determine all vibrational frequencies of the molecule. The IR and Raman spectra of Ge3O3 allow for the unambiguous assignment of a highly symmetric D- 3h ring structure for this molecule, as it has been proposed by other authors. In contrast we find that the previously assumed ring structur e for Ge4O4 is incompatible with the measured IR and Raman spectra, as well as with the results of ab initio calculations. Instead a heteroc ubanelike structure, that is found for the heavier homologus molecules of Sn and Pb, is adopted in this case. (C) 1998 American Institute of Physics.