K W Hipps - Orbital Mediated Tunneling in Vanadyl Phthalocyanine Observed in both Tunnel Diode and STM Environments

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      Publication Details (including relevant citation   information):

      Hipps, K. W., Barlow, Dan E., Mazur, Ursula The Journal of   Physical Chemistry B 2000 104 (11)   2444-2447

      Abstract: For the first time orbital mediated   tunneling spectroscopy (OMTS) is reported for the same species,   vanadyl phthalocyanine (VOPc), in both the tunnel diode and STM   environments. IETS and OMTS for a junction of the form   [Al−Al2O3−VOPc−Pb] show both the expected bias symmetry of   vibrational and electronic inelastic electron tunneling   spectroscopy (IETS) bands and the highly bias asymmetric OMTS   band associated with tunneling via direct occupation of the Pc   ring π* orbital. STM studies of submonolayer coverage of VOPc on   Au(111) produce well-resolved submolecular images of the   molecule. Current imaging tunneling spectroscopy (CITS) allows   one to easily identify VOPc islands, and the resulting I−V curves   can be used to generate dI/dV spectra for VOPc and for bare gold   regions. An intense band seen near +1.4 V bias (Au+) is   identified as the same OMTS band as seen in the tunnel diode:    resonance-like tunneling through the Pc ring π* orbital.

      Address (URL): http://dx.doi.org/10.1021/jp994248q