| With a 600mk homebuilt UHV STM system, we studied molecular vibration at the solid surface with inelastic electron tunneling spectroscopy (IETS) of Acetylene single molecules adsorbed on Cu(100) surface. The identification of vibrational IETS features with normalized conductance change (Deltasigma/sigma) as low as 0.24% in dI2/d2V spectra was demonstrated. Five vibrational modes with energy level at 117.70meV (Deltasigma/sigma =0.42%), 84.07meV (Deltasigma/sigma =0.24%), 58.46meV (Deltasigma/sigma =1.18%), 34.80meV (Deltasigma/sigma =0.65% ) and 22.12meV (Deltasigma/sigma =0.40% ) were identified for the first time with STM-IETS. |
