A QM/QM Multilayer Composite Methodology: The ONIOM Correlation Consistent Composite Approach (ONIOM-ccCA)

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• 作者：Somak R. Das ; T. Gavin Williams ; Michael L. Drummond ; Angela K. Wilson
• 刊名：Journal of Physical Chemistry A
• 出版年：2010
• 出版时间：September 2, 2010
• 年：2010
• 卷：114
• 期：34
• 页码：9394-9397
• 全文大小：119K
• 年卷期：v.114,no.34(September 2, 2010)
• ISSN：1520-5215

文摘

A QM/QM approach incorporating the correlation consistent composite approach (ccCA) into the ONIOM multilayer methodology has been implemented. This new multilayer composite scheme, ONIOM-ccCA, enables the accurate prediction of thermochemical properties for systems containing dozens—and potentially hundreds—of atoms. ONIOM-ccCA is used to predict the C−H bond dissociation energies of 18 anthracene and fluorene analogues, containing up to 43 atoms, to within 1.2 kcal mol⁻¹ of experimental values. Several density functional and basis set combinations are evaluated for use as the low level QM layer. The mean absolute deviation (1.2 kcal mol⁻¹) using the most accurate ONIOM-ccCA method, ccCA:B3LYP/cc-pVTZ, is significantly lower than that of an earlier reported multilayer composite scheme [2.4 kcal mol⁻¹, Li, M.-J.; Liu, L.; Fu, Y.; Guo, Q.-X. J. Phys. Chem. B, 2005, 109, 13818]. Thus, through use of ONIOM-ccCA, accurate thermochemical calculations are now feasible for sizable molecular systems of chemical or biological interest.