Surface species formed by the adsorption and dissociation of water molecules on a Ru(0001) surface containing a small coverage of carbon atoms studied by scanning tunneling microscopy

The adsorption and dissociation of water on a Ru(0001) surface containing a small amount (≤3%) of carbon impurities was studied by scanning tunneling microscopy (STM). Various surface species are formed depending on the temperature. These include molecular H₂O, H₂O-C complexes, H, O, OH, and CH. Clusters of either pure H₂O or mixed H ₂O-OH species are also formed. Each of these species produces a characteristic contrast in the STM images and can be identified by experiment and by ab initio total energy calculations coupled with STM image simulations. Manipulation of individual species via excitation of vibrational modes with the tunneling electrons was used as supporting evidence.