Theoretical Surface Science Beyond Gradient-Corrected Density Functional Theory: Water at α-Al2O3(0001) as a Case Study
Theoretical Surface Science Beyond Gradient-Corrected Density Functional Theory: Water at α-Al2O3(0001) as a Case Study
复制标题
DOI：
10.1021/acs.jpcc.9b00407
复制
发表时间：
2019-03-21
影响因子：
3.7
通讯作者：
Saalfrank, Peter
中科院分区：
文献类型：
--
作者：
Heiden, Sophia;Usvyat, Denis;Saalfrank, Peter
分子在周期性固体表面上的吸附、振动和反应的量子化学描述通常基于方法学上的“标准模型”：广义梯度近似（GGA）中的密度泛函理论（DFT），使用平面波基和三维超晶胞。虽然计算效率高的GGA泛函可以是非常成功的，但已知的情况下，他们没有表现得那么好。最重要的是，化学反应的活化能通常被低估，结果计算的反应速率太大。在这项工作中，我们考虑了一个研究得很好的模型系统：水或水片段吸附在Al封端的α-Al 2 O 3（0001）表面作为一个测试床，研究电子结构方法的性能，无论是从DFT和波函数理论。在DFT方面，我们采用了两个GGA交换相关泛函：PW 91和PBE与和没有色散校正，其结果进行比较的混合泛函B3 LYP和HSE 06。此外，我们遵循一个周期性波函数的方法，在当地的二阶Moller-Plesset微扰理论，LMP 2，Hartree-Fock参考的形式。在途中，我们解决的问题所产生的基础集的选择。我们的研究的主要结果如下：（i）DFT-GGA吸附能与混合DFT和LMP 2值合理一致。特别地，对应于不同吸附结构的相对能量之间的偏差在由于缺失色散校正或基组误差而引起的误差范围内。(ii)与相应的混合DFT值相比，氧-氢伸缩模的谐波DFT-GGA振动频率红移了几十个波数。后者与最近的实验数据吻合得更好。(iii)氢扩散反应的活化能被GGA严重低估相比，混合DFT或LMP 2，这反过来是相当可比的。
The quantum chemical description of the adsorption, vibrations, and reactions of molecules at periodic solid surfaces is frequently based on a methodological "standard model": density functional theory (DFT) in the generalized gradient approximation (GGA), using plane wave bases and three-dimensional supercells. Although the computationally efficient GGA functionals can be very successful, cases are known where they do not perform so well. Most importantly, activation energies for chemical reactions are typically underestimated, with the consequence of computed reaction rates being too large. In this work, we consider a well-studied model system: water or water fragments adsorbed on an Al-terminated alpha-Al2O3(0001) surface as a test bed for studying the performance of electronic structure methods, both from DFT and wave function theory. On the DFT side, we employ two GGA exchange correlation functionals: PW91 and PBE with and without dispersion corrections, whose results are then compared to those of hybrid functionals B3LYP and HSE06. Further, we follow a periodic wave function approach in the form of local second-order Moller-Plesset perturbation theory, LMP2, on a Hartree-Fock reference. En route, we address issues arising from the choice of the basis set. The key findings of our study are as follows: (i) DFT-GGA adsorption energies are in reasonable agreement with both hybrid-DFT and LMP2 values. In particular, the deviations between the relative energies, corresponding to different adsorption structures, are in the range of the error due to missing dispersion corrections or the basis set error. (ii) Harmonic DFT-GGA vibrational frequencies for oxygen hydrogen stretch modes are by several tens of wavenumbers red-shifted compared to corresponding hybrid-DFT values. The latter are in much better agreement with recent experimental data. (iii) The activation energy for a hydrogen diffusion reaction is grossly underestimated by GGA compared to hybrid-DFT or LMP2, which in turn are quite comparable.