I. Ignatyev, T. Sundius
Nov 10, 1995
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Influential Citations
4
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Journal
Journal of Molecular Structure-theochem
Abstract
The structure of hexafluorodisiloxane was optimized at different levels of theory up to MP2/6-31G∗, and the vibrational spectrum was calculated and compared with the experimental one. It was shown that at the Hartree-Fock level the simple SCF/3–21 (O∗) basis set gives satisfactory results. The geometry was also optimized at two C2v structures which appear to be saddle points on the SiF3 rotor potential curve. The significant change of the SiOSi angle equilibrium value in the course of the SiF3 group rotation was explained by assuming repulsion between lone pair electrons of fluorines and oxygen. This effect is also revealed in the predicted change in the νasSiOSi frequency on going from the C2 to the C2v structure. This provides the explanation of some unusual features in the vibrational spectra of hexahalodisiloxanes, namely large gas-solid shifts of νas SiOSi and splitting of this mode in the matrices.