ERATO, Nakajima Designer Nanocluster Assembly Project, Japan Science and Technology Agency, 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012, Japan.
J Am Chem Soc. 2014 Feb 5;136(5):1825-31. doi: 10.1021/ja4088456. Epub 2014 Jan 22.
In this study, we investigate the photoexcited electronic states of ferrocene (Fc) molecules adsorbed on an organic insulating surface by two-photon photoemission spectroscopy. This insulating layer, composed of a decanethiolate self-assembled monolayer formed on an Au(111) substrate, enables us to probe the electronically excited states localized at the adsorbed Fc molecules. The adsorbate-specific state is resonantly excited by photons at 4.57 eV, which is 0.5 eV smaller than the energy of the first molecular Rydberg state of free Fc in the gas phase. This result indicates that the electrons are bound to both the excited hole formed in the adsorbate and the positive image charge induced in the substrate. The hybridized electronic characteristics of the adsorbate-specific state are responsible for the strong transition selectivity and short lifetime of the excited state.
在这项研究中，我们通过双光子光电发射光谱研究了吸附在有机绝缘表面上的二茂铁（Fc）分子的光激发电子态。该绝缘层由在 Au(111) 衬底上形成的癸硫醇自组装单层组成，使我们能够探测到吸附在 Fc 分子上的局域电子激发态。通过在 4.57 eV 的光子共振激发吸附物特异性态，其能量比气相中自由 Fc 的第一个分子里德堡态的能量小 0.5 eV。这一结果表明，电子既被吸附物中形成的激发空穴束缚，也被诱导在衬底中的正图像电荷束缚。吸附物特异性态的混合电子特性是激发态强跃迁选择性和短寿命的原因。
