Study of the hydronium ion in water. A combined quantum chemical and statistical mechanical treatment

Abstract

A combined quantum mechanical statistical mechanical method has been used to study the solvation of the hydronium ion in water. The system is divided in three parts, a quantum core (the ion), 89 classical water molecules and a dielectric continuum. The water molecules are represented using a polarizable potential. The first solvation shell of the ion consists of three water molecules linked by hydrogen bonds to the hydrogen atoms of the ion. The calculations show conformations where up to three water molecules directly interact with the oxygen of the ion. The intramolecular bond length in the ion increases by 0.080 a.u. and the angle decreases in 6.9° upon solvation relative to the gas phase value.