Density functional theory study of the conformation and energetics of silanol and disiloxane

Six different exchange-correlation functionals were assessed in a quantum c hemical study of the geometry and energetics of silanol, its conjugated bas e and both conformers of disiloxane, using Dunning's augmented correlation consistent basis set. It was found that the B3LYP and the B3PW91 hybrid fun ctionals perform the best, their performance was comparable with MP2/VQZ ca lculations. A deprotonation energy of -365.4 kcal/mol for silanol was obtai ned at the B3PWB1/AVQZ level. For disiloxane, a very small difference betwe en both disiloxane conformers, 0.037 kcal/mol (extra stabilization for the doubly staggered conformation) and 149.3 degrees for the very sensible Si-O -Si angle was found, or 154.7 degrees temperature corrected (300 K). degree s 2001 Elsevier Science B.V. All rights reserved.