A theoretical study on the interaction of orthosilicic acid with water molecules

Abstract

Understanding the physico-chemical properties of water/silica interfaces is of key importance in different fields. In view of this, the interactions of water molecules, [(H₂O)_n, n = 1–4], with an orthosilicic acid cluster, [Si(OH)₄], has been studied by several theoretical methods. These interactions are found to be stable and increase with the increase in the number of interacting water molecules. SAPT0 calculations on the adducts has suggested that the sequential adsorption of H₂O molecules on the cluster is primarily electrostatic (up to 70 %) followed by induction interactions (∼18–20 %). The dispersion component contributes moderately (∼ 10–15 %) to the stability of these interactions. The IGM analysis has revealed the simultaneous involvement of hydrogen bonding and van der Waals interactions between water molecules and the Si(OH)₄ cluster. The use of the AIMD technique has suggested the stability of water/Si(OH)₄ clusters at room temperature.