High-spin silicon fullerene Si_(60) and its oligomers

摘要

High-spin states of the Si_(60) fullerene and its oligomers are considered semiempirically by using sequential and parallel implementations of the AM1 codes. The states are energetically favorable and nearly degenerated over triplet, quintet, and septet spins. All atoms of the Si_(60) fullerene are in sp~3-configuration, which is supported by atomic spin density in addition to electron density, the latter to be responsible for the formation of chemical bonds. Spotted distribution of spin density over atoms provides molecular magnetism of the molecule. A similar picture is disclosed for oligomers {Si_(60)}_n with n up to 8, which according to computational results should be magnetic with a fractal-like distribution of spin density over atoms. Opposite the latter, composites Si_(60)C_(60) and Si_(60)H_(60) behave conventionally and are nonmagnetic. A way of the Si_(60) fullerene synthesizing is suggested via the above composite product as intermediates. The considered oligomers are proposed as a model of silicon nanofibers observed recently.