Adsorption of Water Dimer on Platinum(111): Identification of the −OH···Pt Hydrogen Bond

Abstract

The fundamental structure of an isolated water dimer on Pt(111) was determined by means of a spectroscopic method using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. Two water molecules on adjacent atop sites form a dimer through a hydrogen bond, and they rotate even at a substrate temperature of 5 K. Action spectroscopy using STM (STM-AS) for water dimer hopping allows us to obtain the vibrational spectrum of a single water dimer on Pt(111). Comparisons between the experiments and theory show that one of the OH groups of the acceptor water molecule points toward the surface to form an -OH···Pt hydrogen bond.