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在和-表面上对二氧化碳吸附点的振动识别

Ismaila Dabo¹, Andrzej Wieckowski, Nicola Marzari

¹Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA. dabo_is@mit.edu

Journal of the American Chemical Society

|August 21, 2007

概括

密度函数理论准确地预测了和-表面上的一氧化碳 (CO) 振动频率. 这种方法正确地模拟了由于的频率变化,即使其他方法在吸附点稳定性方面失败.

科学领域:

表面科学是一门学科.
计算化学的计算化学
材料科学材料科学材料科学

背景情况:

了解吸附分子的振动特性对于催化和表面化学至关重要.
一氧化碳 (CO) 在等过渡金属上的吸附是一种基本的模型系统.
准确预测吸附点稳定性和振动频率仍然是计算方法的挑战.

研究的目的:

为了研究在和-表面上被吸附的CO的振动特性.
评估密度函数理论 (DFT) 方法,特别是Perdew-Burke-Ernzerhof (PBE) 通用梯度近似 (GGA) 的准确性,用于预测C-O拉伸频率和频率转移.
为了阐明C-O频率在共吸附时发生的变化的化学起源.

主要方法:

在PBE-GGA近似中使用了密度功能扰动理论 (DFPT).
对和-表面上吸附的二氧化碳进行了计算.
使用轨道解析分析状态的力和频率密度,以及GGA+U方法来了解频率转移的化学起源.

主要成果:

计算的C-O拉伸频率与实验光谱测量结果非常一致.
在单层吸附时的频率变化得到了准确的预测.
该研究强调了PBE-GGA在预测振动频率方面的成功,与其在预测吸附点稳定性方面的局限性形成鲜明对比.

结论:

DFT计算,特别是PBE-GGA,对于预测吸附CO的绝对振动频率非常准确.
该研究确定了DFT在强化学吸收模式下对振动性质预测的可靠性.
轨道解析分析提供了对控制C-O振动频率转移的电子因素的见解.

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