Robinson David, McDouall Joseph J W
School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
J Phys Chem A. 2007 Oct 4;111(39):9815-22. doi: 10.1021/jp071641k. Epub 2007 Aug 30.
A number of simplifications in defining the reference wave functions used in multireference second-order Møller-Plesset perturbation theory (MRMP2) calculations are studied. The usual multiconfigurational orbital optimization is avoided by using Hartree-Fock or Kohn-Sham orbitals; the complete configuration expansion in the active-space orbitals is replaced by a severely truncated expansion, and the spin-component-scaling idea is applied to the multireference perturbation expansion. We assess these approximations to the full procedure by calculating the barrier heights for 15 processes taken from the Zhao-Gonzalez-Garcia-Truhlar database. Our results suggest that reliable and relatively cheap reference wave functions for MRMP2 calculations can be obtained from the simplifications introduced here. We hope that this will enable the application of the MRMP2 method to a larger range of chemical systems.
研究了多参考二阶莫勒-普列斯特定则微扰理论（MRMP2）计算中定义参考波函数时的一些简化方法。通过使用哈特里-福克或科恩-沙姆轨道避免了通常的多组态轨道优化；活性空间轨道中的完全组态展开被严重截断的展开所取代，并且自旋分量缩放思想被应用于多参考微扰展开。我们通过计算取自赵-冈萨雷斯-加西亚-特鲁哈拉数据库的15个过程的势垒高度来评估这些对完整过程的近似。我们的结果表明，通过此处引入的简化方法可以获得用于MRMP2计算的可靠且相对廉价的参考波函数。我们希望这将使MRMP2方法能够应用于更广泛的化学体系。
