Vibrational Sum-Frequency Spectroscopy of Alkane/Water Interfaces:  Experiment and Theoretical Simulation

Abstract

The vibrational spectra of interfacial water at a series of alkane/water interfaces have been measured using vibrational sum-frequency spectroscopy. The OH stretching modes of water have been used to characterize the water−water and alkane−water interactions present at these hydrophobic/aqueous interfaces; these results are then compared with previous studies of the CCl 4 /H 2 O interface. The results for all alkanes examined are similar and have general spectral characteristics that coincide with the CCl 4 /H 2 O interface. All spectra show weaker hydrogen bonding interactions than have been observed for the vapor/water interface. Molecular dynamics calculations are used to complement the experimental results in obtaining a more complete picture of the interfacial interactions.