Unoccupied electronic states at small domains of organic films

有机薄膜的横向不均匀性常常是高分辨率光谱分析的难点。我们对微斑双光子光电子能谱进行了改进，并将其应用于有机薄膜的空态研究。成功地测量了Pb2+在HOPG上的空能级分散度。时间分辨实验揭示了光激发形成的电子和空穴的散射过程。我们发现Rubrene分子的电子激发增强是由镜像势态介导的。

Lateral inhomogeneity of organic films is frequently troublesome for high-resolution spectroscopy. We have improved the microspot two-photon photoemission spectrometer and applied it to investigate unoccupied states of organic films. The dispersions of the unoccupied levels of lead phthalocyanine film on HOPG were successfully measured. The time-resolved experiment revealed scattering processes of electrons and holes formed by photoexcitation. We have found an enhanced electronic excitation of rubrene molecules mediated by the image potential state.