Тип публикации: статья из журнала
Год издания: 2010
Идентификатор DOI: 10.1016/j.susc.2010.06.019
Ключевые слова: Silver clusters, Paramagnetic defects, Silica, Density functional calculations, Embedded cluster models, A-density, Adsorption complex, Adsorption energies, Ag atoms, Ag clusters, Cluster growth, Density-functional calculations, Density-functional methods, Elastic polarizable environment, Embedded clusters, Non-bridging oxygen, Paramagnetic centers, Silica surface, Silicon atoms, Silver cluster, Adsorption, Complexation, Defect density, Electronic properties, Mechanics, Oxygen, Paramagnetic materials, Point defects, Surface defects
Аннотация: We studied the interaction of small Ag(n) clusters (n = 1-4) with paramagnetic defect centers of a dehydroxylated silica surface using an all-electron scalar relativistic density functional method. The surface and adsorption complexes on it were modeled with an accurate quantum mechanics/molecular mechanics (QM/MM) scheme of embeddПоказать полностьюing QM clusters in an elastic polarizable environment, described at the molecular mechanics level (MM). We analyzed two types of frequent point defects as sites for trapping and growing of Ag clusters: a silicon atom with a dangling bond (E' center), Si center dot, and a non-bridging oxygen center (NBO). Si-O center dot. The Ag clusters interact with these paramagnetic centers forming strong covalent metal-defect bonds. The high adsorption energy allows one to consider the NBO and E' sites as traps of single Ag atoms and as centers of cluster growth. We also explored the effect of adsorption on observable electronic properties of the silver clusters and of the defects of the silica surface. (C) 2010 Elsevier By. All rights reserved.
Журнал: SURFACE SCIENCE
Выпуск журнала: Vol. 604, Is. 19-20
Номера страниц: 1705-1712
ISSN журнала: 00396028
Место издания: AMSTERDAM
Издатель: ELSEVIER SCIENCE BV