Vibrational sum-frequency spectroscopy of akane/water interfaces: Experiment and theoretical simulation

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 CCl4/H2O interface. The results for all alkanes examined are similar and have general spectral characteristics that coincide with the CCl4/H2O 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.