Investigation of Gaussian4 Theory for Transition Metal Thermochemistry

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• 作者：Nicholas J. Mayhall ; Krishnan Raghavachari ; Paul C. Redfern ; Larry A. Curtiss
• 刊名：Journal of Physical Chemistry A
• 出版年：2009
• 出版时间：April 30, 2009
• 年：2009
• 卷：113
• 期：17
• 页码：5170-5175
• 全文大小：106K
• 年卷期：v.113,no.17(April 30, 2009)
• ISSN：1520-5215

文摘

An investigation of the performance of Gaussian-4 (G4) methods for the prediction of 3d transition metal thermochemistry is presented. Using the recently developed G3Large basis sets for atoms Sc−Zn, the G4 and G4(MP2) methods with scalar relativistic effects included are evaluated on a test set of 20 enthalpies of formation of transition metal-containing molecules. The G4(MP2) method is found to perform significantly better than the G4 method. The G4 method fails due to the poor convergence of the Møller−Plesset perturbation theory at fourth-order in one case. The overall error for G4(MP2) of 2.84 kcal/mol is significantly larger than its previously reported performance for molecules containing main-group elements in the G3/05 test set. However, considering the relatively large uncertainties in the experimental enthalpies, the G4(MP2) method performs reasonably well. The performance of other composite methods based on G3 theory [G3(CCSD)//B3LYP and G3(MP2,CCSD)//B3LYP], as well as several density functional methods, are also presented in this paper. The results presented here will assist future development of composite model techniques suitable for use in transition metal-containing systems.