Inelastic tunneling spectroscopy using scanning tunneling microscopy on trans-2-butene molecule: Spectroscopy and mapping of vibrational feature

The vibrational features of trans-2-butene molecules were mapped by inelastic tunneling spectroscopy (IETS) using scanning tunneling microscopy (STM). The vibrational features of v(C-H) in d₂I/dV₂ were mapped and images were obtained by scaling the tip on the surface with the feedback loop activated while modulation voltage was superimposed in the sample voltage. Though vibrational features have been clearly revealed in an atomic scale, their behavior is much more complicated than that has been measured with the conventional IETS. The results differentiated the molecules of trans-2-butene and butadiene through the mapping of the vibrational feature, demonstrating its capability of chemical identification in atomic scale.