Theory of intensities in inelastic-electron tunneling spectroscopy orientation of adsorbed molecules

Materials Meets Concepts in Molecule‐Based Electronics

“…Early theory to describe the effect of the electron-phonon interaction on transport [ 93,94 ] is based on Fermi's Golden Rule expression for incoming and outgoing waves which are evanescent in the tunneling region. As perturbation, one uses the change in the molecular potential due to the coupling to vibrational modes, which modifi es the M th orbital energy through g Mλ in Equation 17 .…”

“…As perturbation, one uses the change in the molecular potential due to the coupling to vibrational modes, which modifi es the M th orbital energy through g Mλ in Equation 17 . As a result of the vibronic coupling, one observes additional peaks in the second derivative of the current with respect to the voltage V [ 94 ] …”

Field, Thermionic, and Secondary Electron Emission Spectroscopy

“…It is well known (see, e.g., Lambe and Jaklevic, 1968;Kirtley and Hall, 1980) that when a molecule is placed at one of the interfaces of a M-I-M (metalinsular-metal) junction, it produces significant structure in the tunneling current versus voltage characteristic. When the second derivative of the current (d 2 //dV2) is plotted against the applied voltage V one sees peaks at certain values of ·v corresponding to vibrational excitation energies of the metal-adsorbed-molecule complex.…”

Probing local electric field and conformational switching in single-molecule break junctions

“…[22][23][24] It was proposed that the IETS intensities for those systems could give insights into the tunnel junctions' environments and the ratios of intensities could give orientational information. 25 In recent years, STM has been used to study structural conformational changes in single molecules and the degree of coupling between molecular vibrational energies to changes in conformation of molecules under study. 26,27 The conformational and orientational structures of molecules are dictated by a delicate balance between the molecule and local environment interactions in addition to the internal mechanics of the molecules.…”