Vibration of H atomic chains on Ni(1 1 0) measured by scanning tunneling microscope (STM) light emission spectroscopy

We have measured the scanning tunneling microscope (STM) light emission spectrum of hydrogen atoms (H) adsorbed on a Ni(1 1 0) surface. The spectrum contains periodic fine structures, whose period corresponds to the vertical vibrational energy of the adsorbed H atom. This energy showed the expected isotope shift when H was replaced by deuterium (D). Hence it is concluded that the periodic structures are caused by the vibrational motion of H.