Molecular-Scale Structure of a Nitrobenzene Monolayer on Si(001)
Molecular-Scale Structure of a Nitrobenzene Monolayer on Si(001)
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Si(001) 上硝基苯单层的分子尺度结构
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
P. Evans
中科院分区：
文献类型：
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作者：
G. Peng;S. Seo;R. Ruther;R. Hamers;M. Mavrikakis;P. Evans
在室温下，将Si（001）（2 × 1）表面暴露于硝基苯气体中，硝基苯分子可以附着在Si（001）表面上。由此产生的单分子层在扫描隧道显微镜图像中缺乏长程有序，但显示出分子局部周期性排列的迹象。自洽平面波密度泛函理论计算发现，在硝基苯的吸附中每个分子获得的能量几乎是恒定的硝基苯覆盖率的函数，它是积极有利的，以形成覆盖率高达一个分子每个Si二聚体。从头算分子动力学（AIMD）模拟表明，氧的迁移转换的初始配置，其中硝基苯分子桥的Si二聚体到较低的能量配置与氧分离的硝基苯苯基。通过AIMD计算确定了先前未知的低能量配置（SiO2键合特征）。计算了O向Si背键迁移的能垒。
Nitrobenzene molecules can be attached to Si-(001) by exposing the Si(001) (2 × 1) surface to nitrobenzene gas at room temperature. The resulting monolayer lacks long-range order in scanning tunneling microscopy images but shows signs of a local periodic arrangement of molecules. Self-consistent plane-wave density functional theory calculations find that the energy gained per molecule in the adsorption of nitrobenzene is nearly constant as a function of nitrobenzene coverage and that it is energetically favorable to form coverages as high as one molecule per Si dimer. Ab initio molecular dynamics (AIMD) simulations show that the migration of oxygen transforms an initial configuration in which the nitrobenzene molecule bridges a Si dimer into lower energy configurations with oxygen separated from the nitrobenzene phenyl group. A previously unknown low-energy configuration, characteristic of SiO2 bonding, is identified by the AIMD calculations. The energy barriers for O migration into Si backbonds are calcu...