Two-membered silicon rings on the dehydroxylated surface of silica
We present extensive modeling of the amorphous silica surface, aimed at connecting its structural and chemical features. beta-cristobalite surfaces are initially studied to model the hydroxylated surfaces. A model reconstruction of the (111) surface is used to define a path leading to the formation of two-membered silicon rings upon dehydroxylation. Subsequently, a realistic model of the amorphous dehydroxylated (dry) surface is produced, by full ab initio annealing of an initial model generated by classical simulation. The presence of surface two-membered silicon rings emerges naturally. A calculation of IR activity yields an associated peak doublet in agreement with experimental data.
Ceresoli
D
Istituto Nazionale per la Fisica della Materia and Dipartimento di Scienza dei Materiali, Universita di Milano-Bicocca, Via Cozzi 53, I-20125 Milano, Italy.
Bernasconi
M
Iarlori
S
Parrinello
M
Tosatti
E