title: New Insights into the Structure of the Vapor/Water Interface from Large-Scale First-Principles Simulations.
abstract: We present extensive ab initio simulations of the molecular arrangements at the vapor/water interface, which provide valuable insights into the interface structure. In particular, the simulations address the controversy of whether there is a significant amount of nondonor configurations at this prototypical interface, using a novel Car-Parrinello-like ab initio molecular dynamics approach. The interface is modeled by a system of 384 water molecules for 125 ps in a two-dimensional periodic slab, the most extensive ab initio molecular dynamics simulation to date. In contrast to previous theoretical simulations and X-ray absorption spectroscopy, but consistent with sum-frequency generation experiments, we observe no evidence for a significant occurrence of acceptor-only species at the vapor/water interface. Besides a distinct surface relaxation effect, we find that only the topmost layers of the interface obey structural order.
authors: †Institute of Physical Chemistry and Center of Computational Sciences, Johannes Gutenberg University Mainz, Staudinger Weg 9, D-55128 Mainz, Germany.|‡Department of Physics, and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.
authors: Thomas D
authors: TD
authors: Kühne
authors: §Graduate School of EEWS (WCU), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors: Tod A
authors: TA
authors: Pascal
authors: ‡Department of Physics, and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.
authors: Efthimios
authors: E
authors: Kaxiras
authors: §Graduate School of EEWS (WCU), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors: Yousung
authors: Y
authors: Jung
keywords: ab initio molecular dynamics; hydrogen-bonding; hydrophobicity; water/vapor interface