Simplified Reference Wave Functions for Multireference Perturbation Theory

详细信息    查看全文

• 作者：David Robinson ; Joseph J. W. McDouall
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：October 4, 2007
• 年：2007
• 卷：111
• 期：39
• 页码：9815 - 9822
• 全文大小：68K
• 年卷期：v.111,no.39(October 4, 2007)
• ISSN：1520-5215

文摘

A number of simplifications in defining the reference wave functions used in multireference second-orderMller-Plesset perturbation theory (MRMP2) calculations are studied. The usual multiconfigurational orbitaloptimization is avoided by using Hartree-Fock or Kohn-Sham orbitals; the complete configuration expansionin the active-space orbitals is replaced by a severely truncated expansion, and the spin-component-scalingidea is applied to the multireference perturbation expansion. We assess these approximations to the fullprocedure by calculating the barrier heights for 15 processes taken from the Zhao-Gonzalez-Garcia-Truhlardatabase. Our results suggest that reliable and relatively cheap reference wave functions for MRMP2 calculationscan be obtained from the simplifications introduced here. We hope that this will enable the application of theMRMP2 method to a larger range of chemical systems.