Ab initio calculations of linear and cyclic forms of molecules and ions of MY2 dichalcogenides with 16 valence electrons

Ab initio calculations of electronic structures, equilibrium geometric parameters, frequencies and relative IR-intensities of normal oscillations and energies of linear D∞h and cyclic C2v isomers of the neutral MY2 (M=Ge, Sn, Pb) molecules, anions MY2- (M=Ga, Tl) and cations MY2+ (M=As, Sb, Bi) of dioxides, disulfides, diselenides and ditellurides with 16 valence electrons in singlet state were performed. It was established, where the D∞h and C2v structures were in close agreement by energy and the cyclic form was more preferable than linear one. The same calculations were made for the molecules and ions of the transition elements Ti, Zr, Ce, Hf; Sc-, Y-, La-, Lu-; V+, Nb+, Ta+ dioxides. All calculations were carried out by means of the GAUSSIAN-98 program. The obtained results support the point of view, that serial ab initio calculations may be especially useful for the sense and prediction of the cases, where the rules of periodicity are violated