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Quantum-chemical simulation of the incorporation of a Li2O molecule into vitreous B2O3 and SiO2статья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
- Авторы: Kondakova O.A., Dembovsky S.A., Zyubin A.S.
- Журнал: Glass Physics and Chemistry
- Том: 25
- Номер: 5
- Год издания: 1999
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 441
- Последняя страница: 448
- Аннотация: The incorporation of alkali metal oxide into a continuous random network of vitreous boron and silicon oxides is simulated within the cluster approximation at the semiempirical MNDO and MNDO-PM3 levels. It is found that, for g-B2O3, the oxygen atom of a Li2O molecule readily forms an additional bond with the threefold-coordinated boron atom entering into the layer of a continuous random network, irrespective of whether the network layer is built up from boroxol rings or BO3 triangles. The process is accompanied by a considerable decrease in the energy of oxygen atom. One of the Li+ cations can readily travel around thus formed tetrahedron, which facilitates the interaction of the terminal oxygen atom with the boron atom of the second layer. This brings about the formation of the B-O-B bridge, which links a layered continuous random network into the three-dimensional network. The Li+ cations are arranged in the vicinity of the BO4 tetrahedra predominantly along the edges. The incorporation of alkali metal oxide into silicate glasses results in the breaking of three-center oxygen bridges and reduces the network strength. The transformation processes in these glasses are substantially affected by the hypervalent configurations whose participation leads to the switching of bonds instead of their breaking, which, in turn, brings about the decrease in potential barriers upon the rearrangement of structural fragments in glasses.
- Добавил в систему: Кондакова Ольга Анатольевна