Crystallography Group, Department of Geosciences, University of Bremen, Klagenfurter Straße 2-4, D-28359 Bremen, Germany.
Department of Geosciences, University of Padova, Via G. Gradenigo 6, I-35131 Padova, Italy.
J Chem Phys. 2017 May 7;146(17):174111. doi: 10.1063/1.4981528.
Density-functional theory (DFT) calculations incorporating a pairwise dispersion correction were employed to optimize the structures of various neutral-framework compounds with zeolite topologies. The calculations used the PBE functional for solids (PBEsol) in combination with two different dispersion correction schemes, the D2 correction devised by Grimme and the TS correction of Tkatchenko and Scheffler. In the first part of the study, a benchmarking of the DFT-optimized structures against experimental crystal structure data was carried out, considering a total of 14 structures (8 all-silica zeolites, 4 aluminophosphate zeotypes, and 2 dense phases). Both PBEsol-D2 and PBEsol-TS showed an excellent performance, improving significantly over the best-performing approach identified in a previous study (PBE-TS). The temperature dependence of lattice parameters and bond lengths was assessed for those zeotypes where the available experimental data permitted such an analysis. In most instances, the agreement between DFT and experiment improved when the experimental data were corrected for the effects of thermal motion and when low-temperature structure data rather than room-temperature structure data were used as a reference. In the second part, a benchmarking against experimental enthalpies of transition (with respect to α-quartz) was carried out for 16 all-silica zeolites. Excellent agreement was obtained with the PBEsol-D2 functional, with the overall error being in the same range as the experimental uncertainty. Altogether, PBEsol-D2 can be recommended as a computationally efficient DFT approach that simultaneously delivers accurate structures and energetics of neutral-framework zeotypes.
采用包含对色散作用进行修正的密度泛函理论（DFT）计算，对具有沸石拓扑结构的各种中性骨架化合物的结构进行了优化。该计算使用了针对固体的 PBE 泛函（PBEsol），并结合了两种不同的色散修正方案，即 Grimme 提出的 D2 修正和 Tkatchenko 和 Scheffler 提出的 TS 修正。在研究的第一部分，针对总共 14 种结构（8 种全硅沸石、4 种磷铝酸盐沸石型和 2 种密堆积相）的实验晶体结构数据，对 DFT 优化的结构进行了基准测试。PBEsol-D2 和 PBEsol-TS 均表现出优异的性能，明显优于之前研究中确定的性能最佳方法（PBE-TS）。对于那些实验数据允许进行分析的沸石型，评估了晶格参数和键长随温度的变化。在大多数情况下，当实验数据考虑热运动的影响并使用低温结构数据而不是室温结构数据作为参考时，DFT 与实验之间的一致性得到了改善。在第二部分，针对 16 种全硅沸石的相对于α-石英的转变焓进行了基准测试。PBEsol-D2 功能得到了很好的一致性，整体误差与实验不确定度处于同一范围。总之，PBEsol-D2 可以被推荐为一种计算效率高的 DFT 方法，同时提供中性骨架沸石型的准确结构和能量。
