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采用密度泛函方法,以原子簇Pt14为模拟表面,对CN自由基分子在Pt(100)表面上不同吸附位的吸附情况进行了研究.结果表明,CN分子吸附在Pt(100)面上时,通过原子C垂直吸附在表面顶位是其最佳吸附方式,CN键振动频率明显发生蓝移,与实验事实相吻合;而在桥位及四方穴位吸附时CN键振动频率均发生红移.吸附前后,CN分子的σ、π电子与底物间的电荷转移的差异决定了CN键振动频率的不同变化.
The adsorption of CN radicals onto Pt (100) surface was investigated by using density functional theory and cluster analysis of Pt14 as a simulated surface. The results show that when CN molecules are adsorbed on Pt (100) surface, , The vertical adsorption through the atom C on the top of the surface is the best adsorption mode, and the vibration frequency of CN bond is obviously blue-shifted, which agrees well with the experimental fact. However, the CN bond vibration frequency is red-shifted when adsorbed at bridge site and tetragonal sites. Before and after adsorption, the difference of charge transfer between the σ and π electrons of CN molecule and the substrate determines the different changes of the CN bond vibration frequency.