Symmetry Breaking in Spin-Restricted, Open-Shell Hartree-Fock Wave Functions

被引:10
|
作者
Li, Xiangzhu [1 ]
Paldus, Josef [1 ,2 ,3 ]
机构
[1] Univ Waterloo, Dept Appl Math, Quantum Theory Grp, Waterloo, ON N2L 3G1, Canada
[2] Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada
[3] Univ Waterloo, GWC2, Waterloo, ON N2L 3G1, Canada
关键词
Hartree-Fock stability conditions; broken-symmetry solutions; oxygen and boron molecule ground state; symmetry-breaking; UNITARY-GROUP-APPROACH; ELECTRON CORRELATION-PROBLEM; COUPLED-CLUSTER APPROACH; INDEPENDENT-PARTICLE MODEL; STABILITY CONDITIONS; MOLECULAR-SYSTEMS; EQUATIONS; POLYENES;
D O I
10.1002/qua.22098
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
Relying on a unitary group approach (UGA) to coupled-cluster (CC) theory for open-shell systems we formulate a spin-free analogue of Thouless' theorem and derive stability conditions for spin-restricted, open-shell Hartree-Fock (ROHF) The formalism is illustrated on the ground states of the oxygen and boron molecules. For the O-2 molecule, the broken-space-symmetry solution appears already for a slightly stretched O-O bond. For the B-2 molecule we find a broken-symmetry solution even at the equilibrium geometry and, in fact, in almost an entire region of intermolecular separations. (C) 2009 Wiley Periodicals, Inc. Int J Quantum Chem 109: 1756-1765, 2009
引用
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页码:1756 / 1765
页数:10
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