Coupled-cluster approach to the many-body perturbation theory for open-shell systems. [Bloch equation]
A new approach to the diagrammatic formulation of many-body perturbation theory for open-shell systems is presented. The formalism is based on a generalized form of the Bloch equation that also generates the Rayleigh--Schroedinger perturbation expansion for a system with several open shells. Second quantization in the particle-hole formulation is used together with Wick's theorem in order to derive graphical rules in the usual way. The linked-diagram property of the wave operator and of the effective interaction is shown by expanding the wave operator in terms of normal products of connected diagram clusters, in analogy with the exp(S) formalism of Coester and Kuemmel for closed-shell systems. Self-consistent coupled-cluster equations are derived for the open-shell case from the generalized Bloch equation by a straightforward extension of the procedure of Cizek and Paldus. The application of such equations for investigating different properties of open-shell atoms is discussed. 56 references.
- Research Organization:
- Chalmers Univ. of Technology, Goeteborg, Sweden
- OSTI ID:
- 6323847
- Report Number(s):
- CONF-780396-; TRN: 79-009772
- Journal Information:
- Int. J. Quant. Chem., Symp.; (United States), Vol. 12; Conference: International symposium on atomic, molecular, and solid-state theory, collision phenomena and computational methods, Flagler Beach, FL, USA, 12 Mar 1978
- Country of Publication:
- United States
- Language:
- English
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ATOMS
ELECTRONIC STRUCTURE
MANY-BODY PROBLEM
PERTURBATION THEORY
BLOCH EQUATIONS
DIAGRAMS
QUANTUM OPERATORS
RAYLEIGH-SCHROEDINGER FORMULA
SECOND QUANTIZATION
SERIES EXPANSION
SHELL MODELS
WICK THEOREM
EQUATIONS
MATHEMATICAL MODELS
MATHEMATICAL OPERATORS
NUCLEAR MODELS
640305* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Theory- (-1987)