Abstract

F. Benyettou^1*, S. Hiadsi² and A. Bendraoua¹

Density-functional theory (DFT) within local density approximation (LDA) has been carried out for a sequence of hydrated proton clusters. Optimised structures were odtained for n=0, 1 and 3 for (-OH, H3O+)(H2O)n, complex . Hydronium ion H3O+ and hydroxide ion OH- are found to be the center of the neutral complex (-OH, H3O+). The LDA give shorter hydrogen bond lengths O-H, but slightly longer chemical bond lengths O…H as compared with the Post-Hartree-Fock calculations. We found that the distance O...H successively increases with the number of water molecules added to the neutral complex (-OH, H3O+). The solvent effects on proton transfer energy barriers in clusters have been studied. The harmonic vibrational frequencies and IR intensities of various modes have been generated for all optimised structures. This study was confirmed by vibrational studies of these complexes, our results give excellent agreement with experimental values.

hydrated proton clusters; density functional theory; the proton transfer; ab initio methode; intermolecular interactions; hydrogen bond

[ View HTML Full Text]