Structural characterization of the H2O/CCl4 liquid interface using molecular dynamics simulations

We report a molecular dynamics computer simulation study of the liquid/liquid interface formed by water and carbon tetrachloride (H2O/CCl4) at 298 K. The primary focus of the work is the characterization of the structural features of the interface at a molecular level. The computed density profiles for the aqueous and organic phases and the distribution of surface widths indicate a fairly smooth interface approximately 5-Angstrom thick. Analyses of the water structure near and far from the interface show a significant depletion in the average number of hydrogen bonds in the vicinity of the organic phase with respect to the bulk. The average orientation of the water molecules reveals that close to the interface the dipole moments tend to align parallel to the interfacial plane, while the vector joining the hydrogen atoms points slightly away from this plane. These results are discussed in the light of recently reported nonlinear spectroscopy measurements.