Pecularieties of structure and regrouping of various silicondioxide modifications surface centers in hard dehydroxidation circumstances

Within the framework of the model of molecular cluster the stable surface configurations of dehydroxidated silica were calculated at fixed values of an angle α =SiOSi responding to various SiO2 modifications, a non-empirical method MO LKAO in 6-31 G* basis being used. It was shown that the surface O* atom adjoined to one of Si atoms going out on a surface. It's equidistant from neighbouring Si atoms position (a tetranonial surface cycle) is transitional between the corresponding stable configurations. At angles α > 132° transition of O* from one center to another is hampered (a high energy barrier), at α > 123° ÷ 126° the barrier becomes insignificant (i. e. comparable with an energy of thermal movement) and such transition becomes possible (a relevant surface configuration may be considered as structurally not rigid).