IETS inelastic electron-tunneling

The well-known tetrahedral [Co(NCS)4]2 ion has continued to attract attention from analytical chemists, physical chemists, and spectroscopists. The inelastic electron tunneling (IET) spectrum of (Me4N)2[Co(NCS)4] was compared with IR and Raman spectra of the same complex.359 The vibrational bands due to the Me4N+ were prominent in all three spectra, but Coligand stretches were absent from the IET spectra. The lowest 4 42 4T2 electronic transition was strong in the IET spectrum but absent from the IR spectrum. The electric dipole allowed 4A2 4TX electronic transition was observed in both the IET and IR spectra and no fine structure was observed. Complex formation equilibria between Co11 and SCN- were studied calorimetri-... 

Section 5 is on one particular molecule, p-benzene dithiol. This is one of the most commonly studied molecules in molecular electronic transport junctions [7] (although it is also one of the most problematic). Section 6 discusses a separate measurement, inelastic electron tunneling spectroscopy [8, 9] (IETS). This can be quite accurate because it can be done on single molecules at low temperatures. It occurs because of small perturbations on the coherent transport, but it can be very indicative of such issues as the geometrical arrangement in the molecular transport junction, and pathways for electron transport through the molecular structure. 

In contrast to the minimal activity in infrared reflection studies the technique of inelastic electron tunneling spectroscopy (IETS) recently has contributed a large amount of information on monolayer adsorption of organic molecules on smooth metal oxide surfaces,Q),aluminum oxide layers on evaporated aluminum. These results indicate that a variety of organic molecules with acidic hydrogens, such as carboxylic acids and phenols chemisorb on aluminum Oxide overlayers by proton dissociation - 1 — and that monolayer coverage can be attained quite repro-ducibly by solution doping techniques. - The IETS technique is sensitive to both infrared and Raman modes. — However, almost no examples exist in which Raman il and or infrared spectra have been taken for an adsorbate/substrate system for which IETS spectra have been observed. 

Due to the high density of Rh atoms, no species of the form Rh(C0)2 were formed, however. This is expected to be the case on the (111) surface as well. Weak absorptions between 400 and 575 cm"l were seen and are indicative of metal-absorbate stretching and bending vibrations. Inelastic electron tunneling spectroscopic (IETS) measurements on alumina supported rhodium particles (47, 48, 49) add little new structural information... 

In other studies Allara (27) used FTIR reflection to study the interaction of the oxide film of aluminum with acetic acid in which th aluminum acetate carbonyl stretch peak was found at 1590 cm- > in excellent agreement with the 1589 cm-1 peak determined by inelastic electron tunnelling spectroscopy (IETS), another modern technique for vibrational spectra at metal interfaces. The spectra of acetic acid adsorbed on copper oxide or indium,oxide were about the same. 

In parallel, the related activity was in the field of single-electron shuttles and quantum shuttles [143-153]. Finally, based on the Bardeen s tunneling Hamiltonian method [154-158] and Tersoff-Hamann approach [159,160], the theory of inelastic electron tunneling spectroscopy (IETS) was developed [113-116,161-163],... 

ICS IETS IXS IR Indosyanine Green Inelastic Electron Tunneling Spectroscopy Inelastic X-ray Scattering Infrared... 

One technique recently applied to UE [129,130] is inelastic electron tunneling spectroscopy (IETS) (Section 11.11). The IETS spectrum (dIz/dVz) measured at 4.2 K for a monolayer of fullerene-fczs-[12a.ethylthio-tetrakis(3,4-dibutyl-2-thiophene-5-ethenyl)-5-bromo-3,4-dibu-tyl-2-thiophene] malo-nate, 47, between Al and Pb electrodes [130] exhibited (i) the usual IETS spectrum of intramolecular vibrations and (ii) an elastic component, measured at slightly higher bias V, due to "orbital-mediated tunneling," that is, an... 

---