Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands.
Proc Natl Acad Sci U S A. 2010 Dec 7;107(49):20881-6. doi: 10.1073/pnas.1001098107. Epub 2010 Nov 15.
The accuracy of dynamical models for reactive scattering of molecular hydrogen, H(2), from metal surfaces is relevant to the validation of first principles electronic structure methods for molecules interacting with metal surfaces. The ability to validate such methods is important to progress in modeling heterogeneous catalysis. Here, we study vibrational excitation of H(2) on Cu(111) using the Born-Oppenheimer static surface model. The potential energy surface (PES) used was validated previously by calculations that reproduced experimental data on reaction and rotationally inelastic scattering in this system with chemical accuracy to within errors ≤ 1 kcal/mol ≈ 4.2 kJ/mol [Díaz C, et al. (2009) Science 326:832-834]. Using the same PES and model, our dynamics calculations underestimate the contribution of vibrational excitation to previously measured time-of-flight spectra of H(2) scattered from Cu(111) by a factor 3. Given the accuracy of the PES for the experiments for which the Born-Oppenheimer static surface model is expected to hold, we argue that modeling the effect of the surface degrees of freedom will be necessary to describe vibrational excitation with similar high accuracy.
反应性散射分子氢（H2）从金属表面的动力学模型的准确性与验证用于分子与金属表面相互作用的第一性原理电子结构方法相关。验证此类方法的能力对于推进异相催化的建模具有重要意义。在这里，我们使用 Born-Oppenheimer 静态表面模型研究了 H2 在 Cu(111)上的振动激发。先前使用计算验证了所使用的势能面（PES），该计算以化学精度（误差≤1 kcal/mol ≈ 4.2 kJ/mol）重现了该体系中反应和旋转非弹性散射的实验数据[Díaz C等人。（2009）科学 326：832-834]。使用相同的 PES 和模型，我们的动力学计算低估了振动激发对以前从 Cu(111)散射的 H2 的飞行时间谱的贡献，其因子为 3。考虑到 PES 对于 Born-Oppenheimer 静态表面模型预期适用的实验的准确性，我们认为将表面自由度的影响建模为具有类似高精度描述振动激发是必要的。
