Molecular Application of a State Specific Multi-Reference Brillouin-Wigner Perturbation Theory  

作　　者：H.Aksu 

机构地区：[1]Department of Physics,Bilecik University

出　　处：《Chinese Physics Letters》2016年第2期22-25,共4页中国物理快报（英文版）

基　　金：Supported by the Scientific and Technological Research Council of Turkey(TUBITAK)under Grant No 2219-1/2013

摘　　要：The single reference second order Brillouin-Wigner perturbation theory recently developed, which eliminates its size-extensivity error, has been generalized to state-specific, multi-reference （SS-MR）, BWPT2 providing a size-extensive correction to the electron correlation problem for systems that demand the use of a multi-reference function. Illustrative numerical tests of the size-extensivity corrections are made for widely used molecules in their ground states, which are pronounced multi-reference characteristics. We have implemented two-reference and three-reference cases for CH2, BH and bond breaking process in the ground states of HF molecules. The results are compared with the rigorously size-extensive methods such as the M^ller-Plesset perturbation theory, i.e., MP2, full configuration interaction （Full-CI） and allied methods using the same basis sets.The single reference second order Brillouin-Wigner perturbation theory recently developed, which eliminates its size-extensivity error, has been generalized to state-specific, multi-reference （SS-MR）, BWPT2 providing a size-extensive correction to the electron correlation problem for systems that demand the use of a multi-reference function. Illustrative numerical tests of the size-extensivity corrections are made for widely used molecules in their ground states, which are pronounced multi-reference characteristics. We have implemented two-reference and three-reference cases for CH2, BH and bond breaking process in the ground states of HF molecules. The results are compared with the rigorously size-extensive methods such as the M^ller-Plesset perturbation theory, i.e., MP2, full configuration interaction （Full-CI） and allied methods using the same basis sets.

关 键 词：of in Molecular Application of a State Specific Multi-Reference Brillouin-Wigner Perturbation Theory FCI CCSD CISD RHF MRCI CASSCF for been MP is 

分 类 号：O561[理学—原子与分子物理]