DIAMOND-LIKE PHASES OF SILICON
The classification scheme of silicon phases containing atoms with the same degree of hybridization close to sp <sup>3</sup> is proposed. The possibility of the existence of the twenty-eight silicon phases, a description of the structural parameters and properties of twenty-five of which are presented in this article for the first time. We have the geometry optimization of the cluster structures of silicon phases by semiempirical quantum-mechanical AM1 method. Structural characteristics and some properties are calculated. It was found that the difference in the properties of silicon phases depends on the degree of structure deformation. The X-ray patterns of all the proposed phases of silicon are calculated.