Water clusters in liquid organic matrices of different polarity

Abstract

The cluster structure of water is continuously a subject of intense scientific discussion. Because of the electronic and structural characteristics, the experimental studies still present a great challenge. In this work, the water clusters formed in organic liquid matrices of different polarities are studied. Various chlorine hydrocarbons differing in dipole moment were used as dispersing media, namely: carbon tetrachloride, chloroform, dichloromethane and 1,2-dichloroethane. Simple infrared absorption spectroscopy combined with Molecular Dynamics simulations and Density Functional Theory calculations were found to be a very effective tool for the precise determination of the water cluster structure. For the first time, the correlation between experiments and computations is presented at this level of accuracy. The main results show that a higher polarity of the organic matrix favours the formation of stable, small, and cyclic water clusters, while in the nonpolar matrix water molecules tend directly to phase separation on the macroscopic scale. Moreover, the size of the clusters formed by water molecules strongly depends on the water content in the matrix.