Density functional Born-Oppenheimer molecular dynamics (BOMD) is applied to study the evolution of geometry and 29Si NMR chemical shifts of Si(OH)4, which is the smallest zeolite precursor. Inclusion of water-precursor and water-water interactions is needed to obtain the NMR chemical shift in close agreement with experiment. The solvent influences the structural (SiOH angles) and electronic (polarization) parameters of the monomer. A linear correlation between the <SiOH> angles and the NMR chemical shifts is found. It is shown that the experimental NMR shift is indeed a sampling over a wide range of monomer conformations which varies over 50 ppm on the microscopic scale.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry