The initial implementation and applications of a general active space coupled cluster method

被引:193
作者
Olsen, J [1 ]
机构
[1] Aarhus Univ, Dept Chem, DK-8000 Aarhus, Denmark
关键词
D O I
10.1063/1.1290005
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
A general coupled cluster method that allows arbitrary excitations from a single reference-determinant is proposed and tested. The method is based on a generalization of the formalism of spin-strings and provides a unified method for the storage and manipulation of coupled cluster operators. An initial implementation of the method is discussed and used to study the convergence of the coupled cluster hierarchy for H2O and CH2 at equilibrium geometry, employing up to eightfold excitations. The energy and wave function contributions of the various excitation levels are examined. The dissociation curve of HF is also studied. Using single and double excitations from a minimal active space, the coupled cluster dissociation curve for HF shows a largest deviation from full configuration interaction curve of 1.3 mE(h), which decreases by an order of magnitude up on the addition of triple excitations out of the active space. (C) 2000 American Institute of Physics. [S0021-9606(00)30537-2].
引用
收藏
页码:7140 / 7148
页数:9
相关论文
共 25 条
[1]  
Adamowicz L, 1998, MOL PHYS, V94, P225, DOI 10.1080/00268979809482311
[2]  
[Anonymous], J MOL STRUCT THEOCHE
[3]  
BARTLETT RJ, 1995, MODERN ELECT STRUCTU, P1047
[5]   The prediction of molecular equilibrium structures by the standard electronic wave functions [J].
Helgaker, T ;
Gauss, J ;
Jorgensen, P ;
Olsen, J .
JOURNAL OF CHEMICAL PHYSICS, 1997, 106 (15) :6430-6440
[6]  
Helgaker T., 2002, Molecular Electronic-Structure Theory
[7]   THE AUTOMATED SOLUTION OF 2ND QUANTIZATION EQUATIONS WITH APPLICATIONS TO THE COUPLED CLUSTER APPROACH [J].
JANSSEN, CL ;
SCHAEFER, HF .
THEORETICA CHIMICA ACTA, 1991, 79 (01) :1-42
[8]   Highly accurate calculations of molecular electronic structure [J].
Klopper, W ;
Bak, KL ;
Jorgensen, P ;
Olsen, J ;
Helgaker, T .
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, 1999, 32 (13) :R103-R130
[9]  
KNOWLES PJ, 1984, CHEM PHYS LETT, V111, P313
[10]   EXCITATION-ENERGIES OF BH, CH2 AND NE IN FULL CONFIGURATION-INTERACTION AND THE HIERARCHY CCS, CC2, CCSD AND CC3 OF COUPLED-CLUSTER MODELS [J].
KOCH, H ;
CHRISTIANSEN, O ;
JORGENSEN, P ;
OLSEN, J .
CHEMICAL PHYSICS LETTERS, 1995, 244 (1-2) :75-82