ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The role of electron correlation effects on the bond-length alternation in linear metalliclike systems, as modeled by cyclic polyenes CNHN, N = 2n = 4v + 2, v = 1,2,…, is examined using the coupled cluster approach in the localized Wannier basis formalism. A recently developed approximate coupled pair approach which accounts for connected quadruply excited clusters is employed together with various truncation schemes for the localized doubly-excited cluster components. It is found that for the physical value of the coupling constant, the electron correlation has only a very slight effect on the potential energy curves, yielding almost the same values for both the magnitude of the bond-length alternation and for the stabilization energy relative to the symmetric equidistant structures as the restricted Hartree-Fock theory. This is in contrast to a strongly correlated region where the correlation effects stabilize the undistorted non-alternating structures. Different mechanisms of the bond-length alternation or Peierl's distortion as implied by a simple Hückel Hamiltonian and by the Pariser-Parr-Pople Hamiltonian models are also pointed out.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560280405
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