DISSOCIATION CONSTANTS OF SILANOL GROUPS OF SILIC ACIDS: QUANTUM CHEMICAL ESTIMATIONS

Dissociation constants of silanol groups on the silica surface are calculated with the DFT quantum chemical method using B3LYP and M06 functionals. Structural features of silanol fragments and the presence of hydrogen-bonded water clusters are shown to have significant effects on pK(a) values of silanol groups. In particular, pK(a) values are shown to vary widely depending on the features of the system of hydrogen bonds.