A fusion of the closed-shell coupled cluster singles and doubles method and valence-bond theory for bond breaking.
J Chem Phys
; 137(11): 114103, 2012 Sep 21.
Article
en En
| MEDLINE
| ID: mdl-22998245
ABSTRACT
Closed-shell coupled cluster singles and doubles (CCSD) is among the most important of electronic-structure methods. However, it fails qualitatively when applied to molecular systems with more than two strongly correlated electrons, such as those with stretched or broken covalent bonds. We show that it is possible to modify the doubles amplitudes to obtain a closed-shell CCSD method that retains the computational cost and desirable features of standard closed-shell CCSD, e.g., correct spin symmetry, size extensivity, orbital invariance, etc., but produces greatly improved energies upon bond dissociation of multiple electron pairs; indeed, under certain conditions the dissociation energies are exact.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
J Chem Phys
Año:
2012
Tipo del documento:
Article
País de afiliación:
Estados Unidos