Formation of the cyclic ice hexamer via excitation of vibrational molecular modes by the scanning tunneling microscope

Starting from water monomers adsorbed on Cu(111), we have induced the formation of small ice clusters via the tip of a low temperature scanning tunnelling microscope. We show that diffusion, formation, and structural changes of clusters are induced by electrons coupling to vibrational modes of the molecule. The manipulation transfers enough energy into the system to induce stable clusters both two-dimensional and three-dimensional ones, including the important cyclic hexamer. Only the three-dimensional clusters develop a localized gap around the Fermi energy of ≈76 meV, which varies for different positions on a cluster.