Modeling Parameters of Interest in Sol-Gel Process (pp. 319-325)
Authors: Adrian Beteringhe, Maria Zaharescu, and Virgil Badescu
Abstract: In this study DFT method involving the hybrid density functional (B3LYP) and 6-31G(d) basis set isused to estimate molecular first hyperpolarizability (ƒÒ) and dipole moment (£g) for the molecular species identified in the first stage of hydrolysis - polycondensation processes and the initial composition of the reaction mixture: Alkoxide: Water: EtOH = 1: 1: 1.75 (HCl, pH = 3.5) (alkoxide = TEOS (tetraethoxysilane)). A comparative study was realized involving the and £g values obtained by DFT method and those calculated using two QSPR (Quantitative Structure ¡V Property Relationship) models (equations 4 and 5) obtained by correlation of ƒÒƒnand £g values obtained by DFT method with the molecular descriptors implemented in the CODESSA program. The QSPR models with four descriptors (equations 4 and 5) have good predictive power and can be used to predict the and £g values for other species obtained in sol-gel process.