Intermolecular correlation effect in sum frequency generation spectroscopy of electrolyte aqueous solution

Molecular dynamics analysis of the sum frequency generation (SFG) spectroscopy was performed to solve the recent controversial problem about liquid–vapor interface of electrolyte aqueous solution [B.C. Garrett, Science 303 (2004) 1146]. The present molecular dynamics analysis revealed a crucial role of ion-water dipolar correlation in the vibrational SFG spectroscopy, which significantly distorts the general relationship between SFG intensity and surface orientational order. The experimental SFG spectra were thereby elucidated from the local structure of interface.