Does HSO exist?

The possible existence of HSO in aqueous sulfuric acid is analyzed in detail. For bare HSO, the computed free energy barrier for the exergonic transformation of HSO into the HSOHO complex is only 3.8 kcal mol.

Modelling nano-clusters and nucleation.

We review the growing role of computational techniques in modelling the structures and properties of nano-particulate oxides and sulphides. We describe the main methods employed, including those based on both electronic structure and interatomic potential approaches. Particular attention is paid to the techniques used in searching for global minima in the energy landscape defined by the nano-particle cluster.

H-Bond interactions between silicates and water during zeolite pre-nucleation.

The relative strength of water-water, water-silicate and silicate-silicate interactions are studied, in order to explain the low solubility of the monomer (Si(OH)(4)), and determine the degree of dispersion of silicate clusters in solution during the hydrothermal synthesis of zeolites. We will show how the hydrogen bond interactions between water and monomeric silicate species are similar to that in pure water, whilst monomer-monomer interactions are stronger. However, when larger silicate species are also considered we find the relative hydrogen-bonding strength to follow: water-water < silicate-water < silicate-silicate.

An approach to hydration of model silica materials by exploring their multiple minima hypersurfaces. The role of entropy of association.

The influence of molecular water on the structure and formation of silica clusters is modeled with the use of the MMH (multiple minima hypersurfaces) approach. It combines quantum chemical Hamiltonians for the calculation of the internal energy with statistical modeling and formulas for the calculation of thermodynamic functions of association. The structures of the most probable clusters of hydration and some properties of the association with water are proposed.