The formation of (NO)3 on Cu(111) was recently reported based on scanning tunneling microscopy observations [A. Shiotari et al., J. Chem. Phys. 141, 134705 (2014)]. We herein report studies into this system using electron energy loss spectroscopy and verify the above findings through vibrational analysis. For the surface covered with mixed isotopes of N(16)O and N(18)O, we observed four peaks corresponding to N-O stretching vibrations, which were ascribed to the four isotopic combinations of the trimer. Dynamic coupling within the trimer was evaluated from model calculations of the coupled oscillators. Furthermore, we observed hindered rotation and translation modes in the dipole scattering regime, suggesting that the molecular axis is tilted from the surface normal. These results provide spectroscopic support for the formation of (NO)3 on Cu(111).

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We report the novel structure of a water–NO (nitric oxide) complex on Cu(111) by using scanning tunneling microscopy, electron energy loss spectroscopy, and noncontact atomic force microscopy. The fundamental motif of the complex is a triangular cluster, including four NO molecules and three water molecules. As coverage increases, the complex grows into a chain structure on the surface. The preferential formation of such unique complexes suggests that there is attractive interaction between water and NO that is strong enough to overcome NO–NO and water–water interactions. The origin of the interaction is argued in terms of electrostatics, where water donates a polar OH group to NO which is negatively charged via electron transfer from the surface.

The interface of π-conjugated organic molecules with metal surfaces plays a crucial role in determining the efficiency of organic-based electronic devices. Because the interface is buried under the molecule, it is often experimentally inaccessible. Here, we propose a way of simultaneous structural and electronic characterization of the interface of the metal−organic system. Using the molecular manipulation technique of scanning tunneling microscope, we conducted a systematic study of geometric and electronic structure on the same footing and identified the atomic-scale correlation between them for copper phthalocyanine molecule on the Au( 110). The energy level of the lowestunoccupied molecular orbital (LUMO) is found to be linked with the number of underlying Au atoms (n = 2−10) at the interface. The LUMO decreases with n in energy and reaches close to the Fermi level, demonstrating explicitly that the electronic property of the molecule is affected by the atomic-scale variation of the interface. The density functional theory calculations reproduced the energy-level shift as a function of n and identified the origin of the correlation.

Raman spectra were measured for carbon-doped SiO 2 thin films prepared by an rf cosputtering method. The changes in the spectra were systematically studied as a function of the annealing temperature. From a detailed analysis of the spectra, the following conclusions were drawn. In the as-deposited films, very small carbon clusters are embedded in the SiO 2 matrices. When the films are annealed at 600°C, graphite-like sp 2 bonds begin to develop in the clusters. Upon annealing with higher temperatures, the size of sp 2 bond clusters increases. However, the growth of graphite microcrystals can be ruled out, since high-resolution transmission electron microscopic images of the samples annealed at 1000°C do not show lattice fringes due to graphite microcrystals. The samples annealed at 1000°C were found to exhibit an extinction hump around 220 nm, very similar to that seen in the interstellar extinction spectra.