skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Orthogonally-spin-adapted coupled-cluster theory for closed-shell systems including triexcited clusters

Abstract

The orthogonally-spin-adapted form of the nonlinear system of equations for the extended coupled-pair many-electron theory, which involves the monoexcited, biexcited, and triexcited states and cluster components, is derived. A diagrammatic approach, based on second quantization, the time-independent Wick theorem, and the graphical methods of spin algebras, is employed. The advantages of using the orthogonally-spin-adapted states and cluster components, rather than the nonorthogonally-spin-adapted ones which have been previously employed, particularly in the triexcited case, are also discussed. It is also shown that the formulas for the direct configuration-interaction method can easily be obtained in compact form from the linear part of the system of extended coupled-pair equations.

Authors:
;
Publication Date:
Research Org.:
Quantum Theory Group, Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
OSTI Identifier:
6092299
Resource Type:
Journal Article
Journal Name:
Phys. Rev., A; (United States)
Additional Journal Information:
Journal Volume: 20:1
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOMIC MODELS; CONFIGURATION INTERACTION; ELECTRON CORRELATION; MOLECULAR STRUCTURE; ELECTRONIC STRUCTURE; CORRELATIONS; MATHEMATICAL MODELS; 640305* - Atomic, Molecular & Chemical Physics- Atomic & Molecular Theory- (-1987)

Citation Formats

Adams, B G, and Paldus, J. Orthogonally-spin-adapted coupled-cluster theory for closed-shell systems including triexcited clusters. United States: N. p., 1979. Web. doi:10.1103/PhysRevA.20.1.
Adams, B G, & Paldus, J. Orthogonally-spin-adapted coupled-cluster theory for closed-shell systems including triexcited clusters. United States. https://doi.org/10.1103/PhysRevA.20.1
Adams, B G, and Paldus, J. 1979. "Orthogonally-spin-adapted coupled-cluster theory for closed-shell systems including triexcited clusters". United States. https://doi.org/10.1103/PhysRevA.20.1.
@article{osti_6092299,
title = {Orthogonally-spin-adapted coupled-cluster theory for closed-shell systems including triexcited clusters},
author = {Adams, B G and Paldus, J},
abstractNote = {The orthogonally-spin-adapted form of the nonlinear system of equations for the extended coupled-pair many-electron theory, which involves the monoexcited, biexcited, and triexcited states and cluster components, is derived. A diagrammatic approach, based on second quantization, the time-independent Wick theorem, and the graphical methods of spin algebras, is employed. The advantages of using the orthogonally-spin-adapted states and cluster components, rather than the nonorthogonally-spin-adapted ones which have been previously employed, particularly in the triexcited case, are also discussed. It is also shown that the formulas for the direct configuration-interaction method can easily be obtained in compact form from the linear part of the system of extended coupled-pair equations.},
doi = {10.1103/PhysRevA.20.1},
url = {https://www.osti.gov/biblio/6092299}, journal = {Phys. Rev., A; (United States)},
number = ,
volume = 20:1,
place = {United States},
year = {Sun Jul 01 00:00:00 EDT 1979},
month = {Sun Jul 01 00:00:00 EDT 1979}
}