Vibrational Sum Frequency Spectroscopy and Molecular Dynamics Simulation of the Carbon Tetrachloride−Water and 1,2-Dichloroethane−Water Interfaces

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Vibrational sum frequency (VSF) spectra calculated using molecular dynamics (MD) simulations are compared with VSF experimental spectra to gain a clearer picture of water structure and bonding at the carbon tetrachloride−water (CCl4−H2O) and the 1,2-dichloroethane−water (DCE−H2O) liquid−liquid interfaces. The VSF spectral response from interfacial water at the CCl4−H2O interface contains spectral features similar to the resonant VSF response of the vapor−water interface and alkane−water interfaces, while the VSF spectrum from the DCE−H2O interface has a low signal with no distinguishing OH stretch spectral features. These MD based spectral calculations show how different bonding interactions at the DCE−H2O interface lead to spectral broadening, frequency shifting, and spectral interferences that are responsible for the difference in the experimentally measured DCE−H2O and CCl4−H2O spectra. The computational results show that weak H2O−H2O interactions are perturbed by the presence of DCE, leading to increa...