Single-molecule reactions and spectroscopy via vibrational excitation

Abstract

Inelastic tunnelling spectra of single C4 hydrocarbon molecules adsorbed on the Pd(110) surface are presented. Experimental evidence is given that the symmetry of the molecular orbital into which the tunnelling electron first enters determines which vibrational modes are excited. The action spectrum for cis-2-butene exhibits most of the vibrational modes that are expected to be excited except for nu (C[double bond]C), which may be because the molecule is pi bonded to the substrate, thus making the lifetime of the excited state short.

Insight into Action Spectroscopy for Single Molecule Motion and Reactions through Inelastic Electron Tunneling

“…3(b)] and curve C for C 4 D 8 [Fig. 3(c)], the spectral fittings are in a excellent agreement with the experimental results, or ðCD 3 Þ, ðCCÞ, and ðCH 3 Þ or ðCD 3 Þ, respectively, in comparison to the HREEL spectrum [29]. When n !…”

“…Curves A and C are best fitted which include three vibrational signals with the energy of (105 AE 5, 129 AE 5, 354 AE 3 meV) and (89 AE 5, 119 AE 5, 262 AE 3 meV), respectively [28]. Based on the results of HREELS [29], the authors assigned the signals at 360 (270) meV to the C-H (C-D) stretch mode, ðCH 3 Þ [ðCD 3 Þ] (356, 259 meV in HREELS), and the signals at $115 ð110Þ meV to the C-C stretch mode ðCCÞ and the CH 3 [CD 3 ] rocking mode ðCH 3 Þ [ðCD 3 Þ]. It was difficult, however, to determine the exact values of for ðCCÞ, ðCH 3 Þ and ðCD 3 Þ because of their narrow spacing.…”

Dissociation pathways of a single dimethyl disulfide on Cu(111): Reaction induced by simultaneous excitation of two vibrational modes

“…8,9 In STM-AS experiments, one measures the yield Y(V) of molecular motions and/or reactions induced by tunneling electrons as a function of V. They observed vibrational fingerprints that manifest themselves as a threshold a) Electronic mail: kmotobayashi@cat.hokudai.ac.jp b) Electronic mail: maki@k.u-tokyo.ac.jp in Y(V), even when not detected with STM-IETS. Because only inelastic tunneling electrons induce the molecular reactions, STM-AS essentially probes all the excitations of vibrational modes that are responsible for the reactions, whereas STM-IETS is only sensitive to inelastic tunneling events that are reflected in the change of the current.…”

Principles and Techniques

“…This resonant tunneling model was experimentally examined by Kawai and her co-workers at RIKEN, Japan. They showed that the vibrational excitation depends on the spatial distribution of the molecular orbitals formed near the Fermi level of metal [27,28].…”