在Si(100) - 2 x 1上被吸附的跨stilbene分子的表面异构化动力学
Damien Riedel1, Marion Cranney, Marta Martin
1Laboratoire de Photophysique Moléculaire, CNRS (UPR 3361), Bât. 210, Centre Universitaire de Paris Sud, F91405 ORSAY, France. damien.riedel@u-psud.fr
Journal of the American Chemical Society
|April 1, 2009
概括
表面吸附显著改变了斯蒂尔分子动态. 扫描道显微镜揭示了新的适配体和可逆的异构和扩散,这些异构和扩散是由表面的电子激发引发的.
科学领域:
- 表面科学是一门学科.
- 分子动力学分子动力学
- 物理化学 物理化学
背景情况:
- 气相中的斯蒂尔分子的光诱导的trans-cis异体化是众所周知的.
- 预计表面上的吸附会显著改变这些分子反应.
- 了解表面吸附的分子行为对于表面化学应用至关重要.
研究的目的:
- 为了研究在Si(100) - 2 x 1表面上被吸附的跨静烯分子的行为.
- 描述由电子激发引起的形状变化和异构化动态.
- 阐明表面相互作用对分子反应的影响.
主要方法:
- 低温扫描道显微镜 (STM) 在5K以图像分子吸附在12K.
- 使用道电子诱导异构和扩散的电子激发.
- 紧密结合方法计算,以确定STM地形和吸附状态.
- 对反应产量的分析,以构建一个定性潜在能量表面.
主要成果:
- 在Si100) - 2 x 1表面上观察到四种stilbene对应物:跨-stilbene (TS),cis-stilbene (CS) 和两个新的异构体 (I) 和I).
- 电子刺激诱导的可逆异构化 (TS<-->I(1) 和CS<-->I(2)) 和扩散.
- 计算的STM地形表示CS和TS的物理吸收.
- 表面的同位素构造 (I(1),I(2) 类似于由表面稳定过渡状态.
- 由于表面充电效应,异构化动态受到表面剂 (n或p类型) 的影响.
结论:
- 表面吸附与气相相比,大大改变了斯蒂尔异构化途径.
- 电子刺激是一种有效的方法来控制分子异构和表面上的扩散.
- 表面稳定了独特的分子构造,并影响了反应动态.
- 表面电荷和电离电位的修饰在表面吸附分子行为中起着关键作用.
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