在Si(100) 上循环添加和其表面转换
1Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
Journal of the American Chemical Society
|March 3, 2005
概括
上的吸附 (100) 有利于 [4+2] 蝶结构,这种结构在热力学和动力学上是稳定的. 其他反应途径,如 [2+2] 循环加法,具有更高的障碍,不太可能发生.
科学领域:
- 计算化学计算化学
- 表面科学是一门学科.
- 材料科学 材料科学 材料科学
背景情况:
- 了解有机分子和半导体表面之间的相互作用对于设计新的电子和催化材料至关重要.
- 表面上的烯等芳香碳化合物的吸附是一个基本的过程,对表面功能和有机电子有影响.
研究的目的:
- 通过ab initio计算,研究在表面上的的吸附配置和反应机制.
- 确定最稳定的吸附结构,并阐明-Si100) 反应的能量格局.
主要方法:
- 综合的初始理论研究,采用多参考扰动理论.
- 检查了五种潜在反应产物,包括 [2+2] 附加物, [4+2] 附加物,四-西格玛结合结构和类似根的结构.
- 计算各种反应途径和相互转换的吸附能量和激活障碍.
主要成果:
- [4+2] 蝶结构被确定为全球最小吸附配置 (-29.0 kcal/mol).
- [4+2]加法机制表现出一个小或零的激活障碍,类似于迪尔斯-阿尔德反应.
- [2+2]循环添加途径具有更高的激活屏障,由于大型能量屏障,随后的异构化到四-西格玛结合结构不太可能来自 [4+2] 产品.
结论:
- [4+2] 蝶结构代表了在Si100上的最热力学稳定和动力学稳健的吸附产物.
- 反应机制与迪尔斯-阿尔德反应有相似之处,尽管醇的芳香性丧失.
- 理论预测表明, [4+2] 添加物是主要产物,对其他配置的异构化可能性有限.
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