Imaging, spectroscopy and manipulation of water on Au(111), from single molecules to nanoscale ice crystals

COLL 221

Heather L. Tierney, heather.tierney@tufts.edu, Ashleigh E. Baber, ashleigh.baber@tufts.edu, and E. Charles H. Sykes, charles.sykes@tufts.edu. Department of Chemistry, Tufts University, 62 Talbot Ave, Medford, MA 02155
Understanding the properties of water is crucial in a vast variety of chemical, physical and biological systems. In particular, adsorption of water on surfaces is a key area of interest in the fields of biophysics, electrochemistry, semiconductors and catalysis. Low-temperature scanning tunneling microscopy (LT-STM) allows us to image the preferred adsorption sites of water on Au(111). Au(111) was chosen as an inert metal with a variety of nucleation sites. We report the structure of water at 7 Kelvin, from single molecules to small ice crystals. STM spectroscopy performed on both the bare Au surface and on ice crystals reveals how the metal's electronic structure (dI/dV) changes as water is absorbed, and which vibrational excitations are present in the ice overlayer (d2I/dV2). We also report the manipulation of individual water molecules and intact ice clusters with the STM tip.