Gleeson Duangkamol
Chemistry Department, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
J Comput Aided Mol Des. 2008 Aug;22(8):579-85. doi: 10.1007/s10822-008-9207-6. Epub 2008 Mar 15.
In this study the results from a series of calculations are reported that probe the influence of the QM cluster size and the extended framework treatment in ONIOM calculations. This is done by comparing the differences in the structures and energetics obtained during simulations of cis-trans isomerisation of butene in H-ZSM-5 at varying level of accuracy. Seven different models have been employed; 3T, 5T and 10T DFT cluster models, and to more effectively encode the extended framework of ZSM-5; 3T:46T, 5T:46T, 10T:46T DFT:MM ONIOM models, and a 46T DFT cluster model. The results show that irrespective of the exact QM cluster size, relatively small gasphase clusters show clear limitations due to the neglect of the extended framework. In particular, the structural and electronic implications of using the different zeolite models have been rigorously assessed using the multivariate statistical method principal components analysis (PCA).
在本研究中，报告了一系列计算结果，这些计算探究了量子力学（QM）簇尺寸和ONIOM计算中扩展框架处理的影响。这是通过比较在不同精度水平下对H-ZSM-5中丁烯顺反异构化进行模拟时获得的结构和能量学差异来实现的。采用了七种不同的模型；3T、5T和10T DFT簇模型，以及为更有效地编码ZSM-5的扩展框架；3T:46T、5T:46T、10T:46T DFT:MM ONIOM模型，和一个46T DFT簇模型。结果表明，无论确切的QM簇尺寸如何，由于忽略了扩展框架，相对较小的气相簇都显示出明显的局限性。特别是，使用不同沸石模型的结构和电子影响已通过多变量统计方法主成分分析（PCA）进行了严格评估。
