Vibrational Sum Frequency Generation Spectroscopy of the Water Liquid-Vapor Interface from Density Functional Theory-Based Molecular Dynamics Simulations.
The vibrational sum frequency generation (VSFG) spectrum of the water liquid-vapor (LV) interface is calculated using density functional theory-based molecular dynamics simulations. The real and imaginary parts of the spectrum are in good agreement with the experimental data, and we provide an assignment of the SFG bands according to the dipole orientation of the interfacial water molecules. We use an instantaneous definition of the surface, which is more adapted to the study of interfacial phenomena than the Gibbs dividing surface. By calculating the vibrational (infrared, Raman) properties for interfaces of varying thickness, we show that the bulk spectra signatures appear after a thin layer of 2-3 Å only. We therefore use this value as a criterion for calculating the VSFG spectrum.
†Department of Physics, Johannes Gutenberg Universitat, Staudingerweg 7, 55099, Mainz, Germany.
Marialore
M
Sulpizi
‡UPMC Université Paris 06, CNRS, ESPCI, UMR 7195, PECSA, F-75005 Paris, France.
Mathieu
M
Salanne
§Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom.
Michiel
M
Sprik
∥LAMBE CNRS UMR8587, Université d'Evry val d'Essonne, Boulevard F. Mitterrand, Bât Maupertuis, 91025 Evry, France.|⊥Institut Universitaire de France, 103 Boulevard St. Michel, 75005 Paris, France.
Marie-Pierre
MP
Gaigeot
DFT-based MD; VSFG vibrational sum frequency generation; linear response; liquid−vapor interface; non-linear susceptibility