Correlated wavefunctions for crystalline solids: multiparameter AMO treatment of the cubic electron gas

Jones, R. S.; Trickey, S. B.

doi:10.1088/0022-3719/17/26/011

Cited by 4 publications

(1 citation statement)

References 27 publications

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“…also Ref. 36), so that only very few studies attempted to go beyond the Hartree-Fock (HF) limit [33,34]. Clearly, any quantum chemical method that is not size extensive, as typified by the configuration interaction (CI) expansion at the doubly excited level (D-CI), must fail completely in the N + 03 limit, where N is the number of electrons.…”

Section: Introductionmentioning

confidence: 99%

Electron correlation in one dimension: Coupled cluster approaches to cyclic polyene π‐electron models

Paldus

Piecuch

1992

Int J of Quantum Chemistry

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Methods accounting for correlation effects in quasi-one-dimensional rr-electron systems and based on the restricted Hartree-Fock (RHF) single determinantal reference state are briefly reviewed as well as their role in the bond length alternation (or dimerization) problem in polyacetylene-like systems, as described by the semiempirical Hamiltonians of the Pariser-ParrPople (PPP) type. Particular attention is given to the r-electron model of cyclic polyene homologous series CNHN, N = 2n = 4u + 2, Y = 1,2,. . . , which can be regarded as an idealized model of one-dimensional metallic-like systems with imposed Born-von KBrmBn boundary conditions when N -+ m. These models provide a useful bridge between the typical aromatic systems, represented by benzene (N = 6) r-electron model, and long linear polyenic chains, since the properties of these systems hardly change once a sufficiently large N (-26 or 30) is reached. It is shown that due to the quasidegenerate character of the RHF reference employed, and the related prominence of connected quadruply excited cluster components in the exact wave function, most of the standard techniques suffer a singular behavior or break down entirely for large enough systems, particularly in the strongly correlated regime. The approximate coupled pair theory that accounts for quadruply excited clusters (ACFQ method) is shown to be free of these shortcomings and is extended to include also approximately the effects of connected triexcited cluster components. These results are compared with other recently examined approximate methods accounting for the tri-and quadruply excited clusters and the proposed ACW+T(ACW) procedure is shown to provide the best results in the whole range of the coupling constant.

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Section: Introductionmentioning

confidence: 99%

Electron correlation in one dimension: Coupled cluster approaches to cyclic polyene π‐electron models

Paldus

Piecuch

1992

Int J of Quantum Chemistry

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Avoiding orthogonality problems in the application of the alternant molecular orbital method to solids

Jones

Trickey

2009

Int. J. Quantum Chem.

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The application of the Alternant Molecular Orbital method to solids has been hampered both by the need to use a cubic Fermi volume as the reference system and by the belief that the AMO state is always an insulating state. We demonstrate here, however, that a simple relabeling of the AMO "occupied" and "virtual" states in an extended zone scheme allows one to use any Fermi volume for the reference state. Furthermore, the AMO state will now represent a metallic or insulating system depending on the presence of partially filled bands. We have applied the method to the interacting electron gas with BCC symmetry and find a metal-insulator transition at approximately r, = 50.

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Correlated wavefunctions for crystalline solids. II. The metal-insulator transition in the cubic electron gas

Jones

Trickey

1985

J. Phys. C: Solid State Phys.

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Correlated wavefunctions for crystalline solids: multiparameter AMO treatment of the cubic electron gas

Cited by 4 publications

References 27 publications

Electron correlation in one dimension: Coupled cluster approaches to cyclic polyene π‐electron models

Electron correlation in one dimension: Coupled cluster approaches to cyclic polyene π‐electron models

Avoiding orthogonality problems in the application of the alternant molecular orbital method to solids

Correlated wavefunctions for crystalline solids. II. The metal-insulator transition in the cubic electron gas

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