Pardini T, Cepek C, Larciprete R, Sangaletti L, Pagliara S, Gotter R, Floreano L, Verdini A, Morgante A, Parmigiani F, Goldoni A
Dipartimento di Fisica, Università di Trieste, Via Valerio 2, 34127 Trieste, Italy.
J Chem Phys. 2005 Feb 1;122(5):54704. doi: 10.1063/1.1834494.
Core level and valence band photoemission measurements combined with near edge x-ray absorption fine structure measurements were performed on a single C(70) layer adsorbed on polycrystalline Al (1 ML-C(70)/Al) (ML-monolayer), pure and doped with sodium atoms. The data obtained from the pure ML chemisorbed on Al surface show a semiconducting behavior of the system, which is characterized by a covalent bond between the adsorbate and the substrate. The same data show also that the C(70) molecules tend to orient themselves with the C(5v) axis perpendicular to the surface in analogy to what observed for 1 ML-C(70)/Cu(111). By doping the sample with sodium atoms a charge transfer from the alkali atoms to the lowest unoccupied molecular orbital (LUMO) of the C(70) molecules takes place, as underlined by the gradual increasing intensity of the C(70) LUMO peak as a function of doping. Nevertheless, no metallic phases are observed for any doping step.
对吸附在多晶铝上的单分子层C(70)（1 ML-C(70)/Al，ML表示单分子层）进行了芯能级和价带光电子能谱测量，并结合近边X射线吸收精细结构测量，该样品为纯样品以及掺杂了钠原子的样品。从化学吸附在铝表面的纯单分子层获得的数据表明该系统具有半导体行为，其特征是吸附质与基底之间存在共价键。同样的数据还表明，与在1 ML-C(70)/Cu(111)上观察到的情况类似，C(70)分子倾向于使C(5v)轴垂直于表面排列。通过用钠原子掺杂样品，发生了从碱原子到C(70)分子最低未占据分子轨道（LUMO）的电荷转移，这由C(70) LUMO峰强度随掺杂的逐渐增加所突显。然而，在任何掺杂步骤中均未观察到金属相。
